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Digitized  by  the  Internet  Archive 

in  2011  with  funding  from 

Boston  Library  Consortium  IVIember  Libraries 


http://www.archive.org/details/steamitsgenerati1904babc 


THE     BABCOCK.    &     WILCOX     CO. 

85  LIBERTY  STREET,  NEW  YORK,  U.  S.  A. 

WORKS  :     BAYONNE,   NEW  JERSEY,   U.   S.   A. 

Directors 

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J.  G.  WARD,   Treasurer  JOHN  E.   EUSTIS  F.  G.   BOURNE 

H.   F.  DE  PUY,  Secretary  C.  A.  MILLER  C.  A.  KNIGHT 


Branch  Offices 


ATLANTA,  GA.,  U.  S.  A.      . 
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SIR  WILLIAM  ARROL 
ARTHUR  T.  SIMPSON 
W.  J.  P.   MOORE 


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I,  Kaiser  AA/ilhelm  Strasse,  Berlin,  Germany,  and  Oberhaussen,  Germany 

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alfonzo  flaquer 
.  John  M.  Sumner  &  Co. 

SHELDON,  GERDTZEN  &  MORGAN 

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a.  F.  Abrahamson,  Jaime  bache 

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Fabriks-Ges. 
BUDAPEST,  Hungary:" DANUBIUS"SCHOENICHENHartm ANN 

BUCHAREST,  Roumania E.  BehlES 

THE  HAGUE,  Holland W.  SCHLUSEN 

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KABET   BURMEISTER  &  WAIN'S  M ASKIN-OG-SKIBSBYGGERI 
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Aktiebolag 
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Vulcan 


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ST.  PETERSBURG,  Russia  ,  .  JOHN  M.  Sumner  &  Co. 
HELSINGFORS,  Finland      .        .        John  M.  Sumner  &  CO. 

PIR/EUS,  Greece A.  ZACHORIOU 

M02UFFERPUR,  Tirhoot,  India  .  Arthur  Butler  &  Co. 
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COLOMBO,  Ceylon  .        .         WALKER,  SONS  &  Co.,  Ltd. 

YOKOHAMA,  Japan B.  A.  Munster 

SOURABAYA,  Java  .         .  Grundel  &  IIELLENDOORN 

WELLINGTON,  New  Zeal.-ind  .  .  .  JAMES  McLellan 
AUCKLAND,  New  Zealand  JOHN  CHAMBERS  &■  SON,  Ltd- 
JOHANNESBURG,  Transvaal  .  .  .  Reunert  &  Lenz 
KIMBERLEY,  South  Africa  .  .  .  .  Reunert  &  Lenz 
VALPARAISO,  South  America  .  .  BALFOUR  LVON  ^t  Co. 
GRAND  CANARY  AND  TENERIFFE  GRAND  Canarv 
COALING  Co.  (of  Liverpool) 


TELEGRAPHIC    ADDRESSES     FOR     ALL     OFFICES     EXCEPT    BERLIN,    ''BABCOCK'* 
FOR     BERLIN     AND     OBERHAUSEN,   "  AQUADUCT" 


■* 


^ 


:^.s^^— ^^- 


v 


STEAM 


ITS    GENERATION    AND     USE 

WITH    CATALOGUE    OF    THE 
MANUFACTURES   OF 

THE    BABCOCK    &   WILCOX    CO. 

85    LIBERTY    ST.,    NEW    YORK 

AND 

BABCOCK    &    WILCOX,    Limited 

ORIEL  HOUSE,  FARRINGDON  ST.,  LONDON 


THIRTY-THIRD  EDITION 

THIRD    ISSUE 

NEW  YORK  AND   LONDON 


1904    ■        ■  ^-\3^'^ 


V" 


•Q 


*■■*■ 


^ 


Copyright,   1902 

BY 

The  Babcock  &  Wilcox  Co. 


Ubc  Iknicftcrbocfjcr  iprcas,  IRcw  jgorft 

►±^ . ^ , 


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ECONOMY  AND  SAFETY  IN  STEAM  GENERATION. 


ECONOMY  IN  THE  USE  OF  COAL  is  a 
matter  of' great  and  growing  importance. 
It  is  estimated  that  the  annual  production  of 
coal  of  the  world  for  the  year  1896  was  583,450,- 
131  tons,  the  leading  producing  countries  being  : 

United  Kingdom, 195,272,000 

United  States, 168,957,264 

Germany, 112,437,741 

France, 28,870,091 

Austria-Hungary, 28,125,000 

Belgium, 21,250,000 

Russia, 7,785,000 

The  report  of  the  Royal  Commission  in  Eng- 
land in  1870  shows  the  distribution  at  that  time 
to  have  been  as  follows  : 

Metallurgy  and  mines,        44  per  cent. 

Domestic  purposes,  including  gas  and  water,        .  26     "       " 

General  manufacturing, 25     "      " 

Locomotion  by  sea  and  land ^     i<      << 

Since  1870  the  electrical  industries  have  been 
established,  employing  an  enormous  amount  of 
power,  so  that  the  foregoing  percentages  are 
probably  very  different  at  the  present  time,  and 
as  a  considerable  part  of  the  coal  used  in  met- 
allurgy and  mines,  as  also  that  for  domestic 
water  supply,  is  used  for  power,  we  shall  not  be 
far  wrong  in  estimating  that  300,000,000  tons  are 
used  annually  for  making  steam.  A  low  esti- 
mate of  the  value  of  this  coal  at  the  place  of  use 
would  be  an  average  of  ^2.50  per  ton,  which 
gives  as  the  present  annual  expenditure  for 
steam  a  sum  equal  to  $750,000,000  ;  from  which 
it  will  be  seen  how  largely  even  a  small  per  cent, 
of  saving  would  add  to  the  wealth  of  the  world. 
It  is  estimated  that  of  the  steam-power  at 
present  in  use  in  the  world,  80  per  cent,  has 
been  added  in  the  last  twenty-five  years,  so  that 
these  figures  are  none  too  large  for  the  present 
time. 

While  manufacturers  and  engineers  have  giv- 
en much  care  to  the  improvement  of  the  steam 
engine,  whereby  they  might  reduce  the  con- 
sumption of  steam  for  a  given  amount  of  power, 
but,  little  attention,  comparatively,  has  been 
given  to  securing  economy  in  its  generation. 


In  fact,  a  large  number  of  the  boilers  in  use  at 
the  present  day  are  substantially  the  same  as 
were  in  common  use  at  the  close  of  the  last  cen- 
tury, and  but  slight  advance  has  been  made  in 
their  economy.  Of  late  years,  however,  steam 
users  have  begun  to  realize  that  there  are 
principles  and  aims  of  equal  prominence,  and 
greater  importance,  to  be  considered  in  choos- 
ing a  boiler,  to  the  selection  of  a  steam  engine. 
Engineering  experience  and  scientific  inves- 
tigation have  established  the  following  as  the 

Requirements  of  a  Perfect  Steam  Boiler. 

ist.  The  best  materials  sanctioned  by  use, 
simple  in  construction,  perfect  in  workmanship, 
durable  in  use,  and  not  liable  to  require  early 
repairs. 

2d.  A  mud-drum  to  receive  all  impurities  de- 
posited from  the  water  in  a  place  removed  from 
the  action  of  the  fire. 

3d.  A  steam  and  water  capacity  sufficient  to 
prevent  any  fluctuation  in  pressure  or  water  level. 

4th.  A  large  water  surface  for  the  disengage- 
ment of  the  steam  from  the  water  in  order  to 
prevent  foaming. 

5th.  A  constant  and  thorough  circulation  of 
water  throughout  the  boiler,  so  as  to  maintain 
all  parts  at  one  temperature. 

6th.  The  water  space  divided  into  sections, 
so  arranged  that,  should  any  section  give  out, 
no  general  explosion  can  occur,  and  the  de- 
structive effects  will  be  confined  to  the  simple 
escape  of  the  contents  ;  with  large  and  free 
passages  between  the  different  sections  to  equal- 
ize the  water  line  and  pressure  in  all. 

7th,  A  great  excess  of  strength  over  any  le- 
gitimate strain;  so  constructed  as  not  to  be 
liable  to  be  strained  by  unequal  expansion, 
and,  if  possible,  no  joints  exposed  to  the  direct 
action  of  the  fire. 

8th.  A  combustion  chamber  so  arranged 
that  the  combustion  of  the  gases  commenced 
in  the  furnace  may  be  completed  before  the 
escape  to  the  chimney. 


*1 


9th.  The  heating  surface  as  nearly  as  possi- 
ble at  right  angles  to  the  currents  of  heated 
gases,  and  so  as  to  break  up  the  currents  and 
extract  the  entire  available  heat  therefrom. 

loth.  All  parts  readily  accessible  for  clean- 
ing and  repairs.  This  is  a  point  of  the  greatest 
importance  as  regards  safety  and  economy. 

nth.  Proportioned  for  the  work  to  be  done, 
and  capable  of  working  to  its  full  rated  capacity 
with  the  highest  economy. 

12th.  The  very  best  gauges,  safety  valves, 
and  other  fixtures. 

Importance  of  Providing  Against  Explosion. 

That  the  ordinary  forms  of  boilers  are  liable  to 
explode  with  disastrous  effect  is  conceded.  That 
they  do  so  explode  is  witnessed  by  the  sad  list  of 
casualties  from  this  cause  every  year,  and  almost 
every  day.  In  the  year  1880,  there  were  170  ex- 
plosions reported  in  the  United  States,  with  a 
loss  of  259  lives,  and  555  persons  injured.  In  1887 
the  number  of  explosions  recorded  were  198, 
with  652  persons  either  killed  or  badly  wounded. 
The  average  reported  for  ten  years  past  has 
been  about  the  same  as  the  two  years  given,  while 
doubtless  many  occur  which  are  not  recorded. 

There  is  no  need  to  resort  to  mysterious  causes 
for  the  destructive  energy  displayed  in  a  boiler 
explosion,  for  there  is  ample  force  confined 
within  it  to  account  for  all  the  phenomena.  Prof. 
Thurston*  estimates  that  there  is  sufficient  stored 
energy  in  a  plain  cylinder  boiler  with  100  pounds 
pressure  of  steam  to  project  it  to  a  height  of  over 
three  and  one-half  miles;  a  "two-flue"  boiler 
about  two  and  one-half  miles  ;  a  "  locomotive ' ' 
at  125  pounds  from  one-half  to  two-thirds  of  a 
mile;  and  a  60  H.  P.  return  "tubular"  at75pounds 
somewhat  over  a  mile  high.  He  says,  "  A  cubic 
foot  of  heated  water  under  a  pressure  of  60  to  70 
pounds  per  square  inch,  has  about  the  same  energy 
as  one  pound  of  gunpowder.  At  a  low,  red  heat, 
it  has  about  forty  times  this  amount  of  energy  in 
a  form  to  be  so  expended. ' '  Speaking  of  water- 
tube  boilers  he  says:  "The  stored  available  en- 
ergy is  usually  less  than  that  of  any  of  the  other 
stationary  boilers,  and  not  very  far  from  the 
amount  stored,  pound  for  pound,  in  the  plain 
tubular  boiler.  It  is  evident  that  their  admitted 
safety  from  destructive  explosion  does  not  come 
from  this  relation,  however,  but  from  the  division 
of  the  contents  into  small  portions,  and  especially 
from  those  details  of  construction  which  make  it 
tolerably  certain  that  any  rupture  shall  be  local. 
A  violent  explosion  can  only  come  of  the  general 
disruption  of  a  boiler  and  the  liberation  at  once 
of  large  masses  of  steam  and  water. ' ' 

*  Transactions  Am.  Soc.  Mec.  Eng.,  Vol.  6,  page  igg. 


The  Hartford  Steam  Boiler  Inspection  and  In- 
surance Company  report  that  up  to  January  i, 
1888,  they  had  inspected,  in  all,  799,582  boilers, 
and  had  discovered  522,873  defects,  of  which 
g3,o22  were  considered  dangerous.  If  now  the 
above  were  a  fair  average  of  the  boilers  in  ordi- 
nary use — and  who  shall  say  they  are  not? — we 
have  the  startling  fact  that  more  thati  one  boiler 
i)i  nine  in  common  use  is  in  a  "dangerous 
condition. ' '  That  more  do  not  explode  is  proba- 
bly due  less  to  intelligent  watchcare  than  to  the 
fortunate  lack  of  all  the  necessary  conditions 
existing  at  one  time. 

Causes  of  Explosion. 

It  is  now  fully  established  by  the  experience 
of  Boiler  Insurance  Associations  in  this  country 
and  England,  that  all  the  mystery  of  boiler  ex- 
plosions consists  in  a  want  of  sufficient  strength 
to  withstand  the  pressure.  This  lack  of  strength 
may  be  inherent  in  the  original  construction,  but 
is  most  frequently  the  effect  of  weakening  of 
the  iron  by  strains  due  to  unequal  expansion 
caused  by  unequal  heating  of  different  portions 
of  the  boiler;  or  it  may  be  due  to  corrosion  from 
long  use  or  improper  setting. 

If  steam  boilers  are  properly  proportioned  and 
constructed,  they  will,  when  new,  be  safe  against 
considerably  more  pressure  than  the  safety  valve 
is  set  to;  and  the  hydrostatic  test,  properly  ap- 
plied, may  discover  faults  in  material,  or  the 
weakening  effects  of  corrosion;  but,  against  the 
danger  resulting  from  unequal  expansion,  ordi- 
nary boilers  have  no  protection;  a  fact  not  prop- 
erly appreciated  by  engineers  or  the  public. 

In  getting  up  steam  many  boilers  will  be  very 
hot  in  some  parts,  while  other  parts  will  be  actu- 
ally cold;  of  course,  under  these  conditions, 
enormous  strains  must  occur  in  some  portions  of 
the  boiler,  which  are  thereby  weakened;  and 
these  strains  being  repeated  every  time  steam  is 
raised,  if  at  no  other  time,  will  eventually  so  far 
destroy  the  strength  of  the  line  or  point  of  great- 
est strain  that  rupture  must  result;  generally  the 
rupture  is  small  and  gradual,  but  sometimes 
large  and  productive  of  disastrous  explosions. 
In  the  boilers  examined  by  the  Hartford  Boiler 
Insurance  Company,  up  to  1888,  24,944  fractures 
in  plates  were  found  in,  at,  or  near  the  seams  or 
through  the  line  of  rivets,  11,259  of  which,  or 
nearly  one  half,  had  arrived  at  a  dangerous  state 
before  discovery. 

Want  of  circulation  of  the  water  in  boilers  is 
a  frequent  and  prolific  cause  of  unequal  expan- 
sion, and  deteriorating  strains,  and  little,  if  any, 
provision  is  made  for  circulation  in  all  ordinary 
construction  of  boilers.     Another  source  of  dan- 


■* 


>>4- 


■^ 


►  -4- 


ger  in  all  ordinary  boilers  is  low  water;  and  con- 
stant vigilance  is  required  to  keep  the  water  at  a 
proper  height.  In  many  boilers  the  fall  of  only 
a  few  inches  in  the  water-line  will  cause  the 
crown-sheet  or  some  other  portion  to  be  exposed 
to  the  direct  action  of  the  fire,  whence  it  becomes 
quickly  overheated,  and  weakened  to  such  an 
extent  that  an  explosion  is  likely  to  occur. 

Another  frequent  cause  of  unequal  expansions, 
and  also  of  weakening  by  burning  and  blistering 
the  iron,  is  the  presence  of  deposit  or  scale  on 
the  heating  surface.  This  is  liable  to  occur  in 
any  boiler,  but  in  very  many  there  is  no  adequate 
provision  for  removing  it  when  formed.  This  is 
particularly  the  case  with  ' '  tubular ' '  and  ' '  loco- 
motive" boilers. 

There  is  good  reason  for  believing  that  most 
of  the  mysterious  explosions  of  boilers  which 
stand  the  Inspector's  test,  and  then  explode  at  a 
much  less  pressure,  are  due  to  the  weakening 
effects  of  unequal  expansions,  for  a  boiler  that 
will  stand  a  hundred  pounds  test  this  week  can- 
not explode  the  next  week  at  fifty  pounds  pres- 
sure, unless  it  has  suddenly  become  wonderfully 
reduced  in  strength,  and  no  corrosion  or  other 
natural  cause,  with  which  we  are  acquainted, 
save  expansion,  can  produce  this  result.  When 
we  consider  that  strains  from  difference  of  ex- 
pansion are  generally  greatest  when  firing  up, 
and  when  there  is  no  pressure  in  the  boiler,  we 
can  see  that  the  time  may  arrive  when  a  crack  is 
started  or  the  parts  weakened,  so  as  to  give  way 
under  a  moderate  pressure  just  after  the  test  has 
been  made;  and  this  is  the  probable  reason  why 
so  many  boilers  explode  in  getting  up  steam,  or 
so  soon  after,  or  upon  pumping  in  cold  water, 
or,  even,  as  in  a  recent  case  in  England,  while 
cooling  off. 

How  to  Provide  Against  Explosions. 

Very  much  thought  and  experiment  have  been 
expended  on  this  problem,  but  though  many 
forms  of  boilers  have  been  produced,  which  have 
attained  practical  safety  from  explosion,  yet  in 
nearly  all  of  them  there  have  been  ignored  cer- 
tain elements  necessary  at  the  same  time  to  make 
them  valuable  as  generators  of  steam  for  practi- 
cal work.  Hence,  the  very  name  of  "safety 
boiler"  has  unfortunately  become,  to  some  per- 
sons, prima  facie  evidence  of  undesirability. 
But  safety  is  not  incompatible  with  any  of  the 
other  essentials  of  a  perfect  steam  generator,  and 
may  be  secured  without  detracting  from  any 
other  desirable  feature. 

The  first  element  of  safety  is  ample  strength. 
This  can  be  best  attained  in  connection  with  thin 
heating  surface,  by  small  diameters  of  parts;  but 


this  must  not  be  carried  so  far  as  to  antagonize 
the  equally  important  features  of  large  capacity 
and  disengaging  surface. 

The  second  and  most  important  element  of 
safety  is  such  a  structure  that  the  original 
strength  cannot  be  destroyed  by  deteriorating 
strains,  from  expansion  or  otherwise.  This  can 
be  attained  in  two  ways — by  rendering  unequal 
expansion  impossible,  or  by  providing  such  elas- 
ticity that,  should  it  occur,  it  can  produce  no 
deteriorating  strain. 

The  third  element  of  safety  is  such  an  arrange- 
ment of  parts  that  when,  through  gross  careless- 
ness or  design,  the  water  becomes  low  and  the 
boiler  overheated,  a  rupture,  if  it  occur,  can  pro- 
duce no  serious  disaster. 

No  surface  which  requires  to  be  "stayed" 
should  be  permitted  in  a  boiler.  It  is  scarcely 
possible,  and  altogether  improbable,  that  such 
stays  are,  or  can  be,  so  adjusted  as  to  bear  equal 
strains.  The  one  sustaining  the  heaviest  strain 
gives  way,  the  others  follow,  as  a  matter  of 
course,  and  a  disastrous  explosion  ensues.  The 
photographic  view  of  the  boiler  which  ex- 
ploded at  Washington,  January  9,  1888,  shows 
how  stay  bolts  act,  and  the  disastrous  explosion 
at  West  Chester,  Pa.,  about  the  same  time,  was 
clearly  due  to  the  giving  way  of  the  stays  which 
were  intended  to  support  the  head. 

Water-tubes  an  Element  of  Safety. 

[/^rom  the  Manufacturer  atid Builder,  Feb.,  755o.] 

Some  recent  actual  occurrences  have  a  very 
suggestive  bearing  upon  the  relative  degree  of 
immunity  from  violent  and  disastrous  explosions 
possessed  by  the  water-tube  and  fire-tube  sys- 
tems of  boiler  construction  respectively. 

The  first  case  is  that  of  an  accident  resulting 
through  gross  carelessness  to  a  steam  boiler  on 
the  water-tube  system  as  constructed  by  Messrs. 
Babcock  &  Wilcox.  The  circumstances  of  the 
case  were  such  as  to  make  the  test  to  which  the 
boiler  was  put  a  most  severe  one,  and  the  fact 
that  the  result  was  not  a  disastrous  explosion 
scores  several  points  in  favor  of  the  water-tube 
system. 


The  boiler  here  referred  to  is  located  in  the 
Brooklyn  Sugar  Refinery,  and  is  rated  at  300 
horse-power,  being  one  of  a  set  of  1500  H.  P. 
Recently,  by  one  of  those  oversights  that  now 
and  then  cost  scores  of  lives  under  the  same  cir- 
cumstances, the  feed-water  was  cut  off,  and  not 
noticed  until  the  water  level  became  so  low  that 


^ 


11 


^ 


^ 


T" 


the  boiler-was  nearly  empty  and  the  tubes  were 
overheated.  The  result  is  shown  above.  One 
of  the  tubes  burst,  and  this  was  the  extent  of  the 
damage,  which  was  speedily  repaired  at  a  cost  of 
|i5,  and  the  works  were  running  the  next  day. 

The  second  case  is  very  analogous,  but  is  even 
more  instructive,  as  the  boiler  was  subjected  to 
a  severer  ordeal  than  the  other.  This  boiler  is 
in  the  Elizabeth  (N.  J.)  jail,  and  was  one  of  the 
same  kind  as  that  in  the  foregoing  case.  It  was 
in  charge  of  one  of  the  convicts,  who,  after  start- 
ing the  fire  as  usual  in  the  morning,  was  sur- 
prised not  to  observe,  after  an  hour  or  so  of 
waiting,  any  signs  of  activity  in  his  steam  gauge. 
This  fact  was  disclosed  to  some  of  the  officials  of 
the  prison,  and  an  investigation  was  instituted  to 
ascertain  the  cause,  disclosing  a  fact  that  at  once 
relieved  the  boiler  from  any  responsibility  for  the 
absence  of  steam — for  there  was  no  water  in  it. 
It  also  showed  that  the  blow-cock  was  wide 
open,  and  had  been  since  the  night  before. 
What  followed,  we  give  in  Mr.  Watson's  own 
words  : 

' '  After  the  syndicate  had  opened  the  furnace 
door  and  seen  the  white  hot  tubes,  it  was  thought 
a  good  idea  to  get  some  water  in  the  boiler  as 
quickly  as  possible  ;  so  they  shut  the  blow-cock 
and  turned  on  the  city  water.  The  result  justi- 
fied their  expectations  ;  steam  was  made  very 
quickly ;  for  a  moment  it  roared  through  the 
safety  valve  with  a  fearsome  sound  ;  and  that  is 
all  that  happened,  beyond  the  renewal  of  a  few 
of  the  tubes,  and  one  steel  casting. ' ' 

What  might  have  happened  had  either  of  these 
boilers  been  fire-tube  instead  of  water-tube  boil- 
ers, we  do  not  pretend  to  say,  but  think  Mr. 
Watson  is  not  far  out  of  the  way  in  venturing  the 
statement  that  "  it  is  not  contrary  to  precedent 
to  say  that,  in  all  probability,  there  would  have 
been  an  opportunity  for  a  coroner's  inquest  and 

a  new  jail." 

Caution  Necessary. 

It  must  not  be  assumed,  however,  that  the  mere 
presence  of  water  tubes  in  a  boiler  will 
make  it  safe.  On  the  contrary,  they  may 
be  combined  with  other  features  exceed- 
ingly dangerous,  such  as  fiat  surfaces, 
stayed  or  unstayed,  as  in  the  "  Phleger" 
boiler  which  exploded  in  Philadelphia 
some  years  ago,  and  the  "  Firminich  " 
boiler  which  exploded  in  St.  Louis, 
Oct.  3d,  1887.  A  number  of  porcupine 
boilers  have  also  been  put  forth  as 
"safe"  because  of  their  water  tubes, 
though  the  large  central  shell  is  made 
like  perforated  cardboard,  by  the  nu- 
merous   holes.      To    make  the  matter 


worse,  expanding  the  tubes  into  these  holes 
seriously  strains  the  metal,  making  a  weak 
construction  weaker   stili. 

That  a  boiler  can  be  made  so  as  to  be  practi- 
cally safe  from  explosion  is  a  demonstrated  fact 
of  which  no  one  at  all  acquainted  with  modern 
engineering  has  any  doubt.  Of  this  class  of  boil- 
ers the  Babcock  &  Wilcox  is  a  pre-eminent  ex- 
ample, from  the  length  of  time  which  it  has  been 
upon  the  market,  the  large  number  which  have 
been  for  years  in  use  under  all  sorts  of  circum- 
stances and  conditions  and  under  all  kinds  of 
management,  without  a  single  instance  of  disas- 
trous explosion. 

The  Babcock  &  Wilcox  water-tube  boiler 
has  all  the  elements  of  safety,  in  connection  with 
its  other  characteristics  of  economy,  durability, 
accessibility,  etc.  Being  composed  of  wrought 
iron  tubes,  and  a  drum  of  comparatively  small 
diameter,  it  has  a  great  excess  of  strength  over 
any  pressure  which  it  is  desirable  to  use.  As 
the  rapid  circulation  of  the  water  insures  equal 
temperature  in  all  parts,  the  strains  due  to  un- 
equal expansion  cannot  occur  to  deteriorate  its 
strength.  The  construction  of  the  boiler,  more- 
over, is  such  that,  should  unequal  expansion 
occur  under  extraordinary  circumstances,  no 
objectionable  strain  can  be  caused  thereby, 
ample  elasticity  being  provided  for  that  purpose 
in  the  method  of  construction. 

In  this  boiler,  so  powerful  is  the  circulation 
that  as  long  as  there  is  sufficient  water  to  about 
half  fill  the  tubes,  a  rapid  current  flows  through 
the  whole  boiler  ;  but  if  the  tubes  should  finally 
get  almost  empty,  the  circulation  then  ceases 
and  the  boiler  might  burn  and  give  out ;  by  that 
time,  however,  it  is  so  nearly  empty  as  to  be 
incapable  of  harm  if  ruptured. 

Its  successful  record  of  over  thirty  years 
proves  that  by  the  application  of  correct  princi- 
ples, the  use  of  proper  care  and  good  material 
in  construction,  a  boiler  can  be  made  so  as  to 
be  in  fact  as  well  as  in  name  a  "  safety  boiler." 


Return  Tubular  Boiler  at  the  Edison  Electric  Light  Co.'s  Works, 

West  Chester,  Pa. 
Exploded  Dec.  17, 1887,  killing  seven  and  wounding  eight  people. 


►i^ 


13 


^ 


THE   THEORY  OF  STEAM  MAKING. 

[Extracts  from  a  Lecture   delivered  by  Geo.  H.  Babcock,  at 
Cornell  University,  1887.*] 

The  chemical  compound  known  as  H^O  exists 
in  three  states  or  conditions — ice,  water,  and 
steam  ;  the  only  difference  between  these  states 
or  conditions  is  in  the  presence  or  absence  of  a 
quantity  of  energy  exhibited  partly  in  the  form 
of  heat  and  partly  in  molecular  activity,  which, 
for  want  of  a  better  name,  we  are  accustomed 
to  call  "latent  heat " ;  and  to  transform  it  frorn 
one  state  to  another  vye  have  only  to  supply  or 
extract  heat.  For  instance,  if  we  take  a 
quantity  of  ice,  say  one  pound,  at  absolute  zerof 
and  supply  heat,  the  first  effect  is  to  raise  its 
temperature  until  it  arrives  at  a  point  492  Fah- 
renheit degrees  above  the  starting  point.  Here 
it  stops  growing  warmer,  though  we  keep  on 
adding  heat.  It,  however,  changes  from  ice  to 
water,  and  when  we  have  added  sufficient  heat 
to  have  made  it,  had  it  remained  ice,  283°  hotter 
or  a  temperature  of  315°  by  Fahrenheit's  ther- 
mometer, it  has  all  become  water,  at  the  same 
temperature  at  which  it  commenced  to  change, 
namely,  492°  above  absolute  zero,  or  32°  by 
Fahrenheit's  scale.  Let  us  still  continue  to  add 
heat,  and  it  will  now  grow  warmer  again, 
though  at  a  slower  rate  —  that  is,  it  now  takes 
about  double  the  quantity  of  heat  to  raise  the 
pound  one  degree  that  it  did  before  —  until  it 
reaches  a  temperature  of  212°  Fahrenheit,  or 
672°  absolute  (assuming  that  we  are  at  the  level 
of  the  sea).  Here  we  find  another  critical 
point.  However  much  more  heat  we  may  apply, 
the  water,  as  water,  at  that  pressure,  cannot  be 
heated  any  hotter,  but  changes  on  the  addition 
of  heat  to  steam  ;  and  it  is  not  until  we  have 
added  heat  enough  to  have  raised  the  tempera- 
ture of  the  water  966°,  or  to  1,178°  by  Fahren- 
heit's thermometer  (presuming  for  the  moment 
that  its  specific  heat  has  not  changed  since  it  be- 
came water),  that  it  has  all  become  steam, 
which  steam,  nevertheless,  is  at  the  temperature 
of  212°,  at  which  the  water  began  to  change. 
Thus  over  four  fifths  of  the  heat  which  has  been 
added  to  the  water  has  disappeared,  or  become 
insensible  in  the  steam  to  any  of  our  instruments. 

It  follows  that  if  we  could  reduce  steam  at  at- 
mospheric pressure  to  water,  without  loss  of 
heat,  the  heat  stored  within  it  would  cause  the 
water  to  be  red  hot ;  and  if  we  could  further 
change  it  to  a  solid,  like  ice,  without  loss  of 
heat,  the  solid  would  be  white  hot,  or  hotter 
than  melted  steel  —  it  being  assumed,  of  course, 

*See  Scientific  Americaii  Supplement,  624,  625,  Dec,  1887. 

t46o°  below  the  zero  of  Fahrenheit.  This  is  the  nearest  ap- 
proximation in  whole  degrees  to  the  latest  determinations  of  the 
absolute  zero  of  temperature. 


that  the  specific  heat  of  the  water  and  ice  re- 
main normal,  or  the  same  as  they  respectively 
are  at  the  freezing  point. 

After  steani  has  been  formed,  a  further  addi- 
tion of  heat  increases  the  temperature  again  at  a 
much  faster  ratio  to  the  quantity  of  heat  added, 
which  ratio  also  varies  according  as  we  maintain 
a  constant  pressure  or  a  constant  volume  ;  and 
I  am  not  aware  that  any  other  critical  point  ex- 
ists where  this  will  cease  to  be  the  fact  until  we 
arrive  at  that  very  high  temperature,  known  as 
the  point  of  dissociation,  at  which  it  becomes 
resolved  into  its  original  gases. 

The  heat  which  has  been  absorbed  by  one 
pound  of  water  to  convert  it  into  a  pound  of 
steam  at  atmospheric  pressure  is  sufficient  to 
have  melted  three  pounds  of  steel  or  thirteen 
pounds  of  gold.  This  has  been  transformed 
into  something  besides  heat ;  stored  up  to  reap- 
pear as  heat  when  the  process  is  reversed.  That 
condition  is  what  we  are  pleased  to  call  latent 
heat,  and  in  it  resides  mainly  the  ability  of  the 
steam  to  do  work. 


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QUANTITY  OF  HEAT  IIS  BRITISH  THERMAL  UNITS. 

The  diagram  shows  graphically  the  relation  of 
heat  to  temperature,  the  horizontal  scale  being 
quantity  of  heat  in  British  thermal  units,  and  the 
vertical  temperature  in  Fahrenheit  degrees,  both 
reckoned  from  absolute  zero  and  by  the  usual 
scale.  The  dotted  lines  for  ice  and  water  show 
the  temperature  which  would  have  been  obtained 


>--4- 


15 


^'^ 


if  the  conditions  had  not  changed.  The  Hnes 
marked  "gold"  and  "steel  "  show  the  relation 
to  heat  and  temperature  and  the  melting  points 
of  these  metals.  All  the  inclined  lines  would  be 
slightly  curved  if  attention  had  loeen  paid  to  the 
changing  specific  heat,  but  the  curvature  would 
be  small.  It  is  worth  noting  that,  with  one  or 
two  exceptions,  the  curves  of  all  substances  lie 
between  the  vertical  and  that  for  water.  That  is 
to  say,  that  water  has  a  greater  capacity  for  heat 
than  all  other  substances  except  two,  hydrogen 
and  bromine. 

In  order  to  generate  steam,  then,  only  two 
steps  are  required  :  First,  procure  the  heat,  and, 
second,  transfer  it  to  the  water.  Now,  you  have 
it  laid  down  as  an  axiom  that  when  a  body  has 
been  transferred  or  transformed  from  one  place  or 
state  into  another,  the  same  work  has  been  done 
and  the  same  energy  expended,  whatever  may 
have  been  the  intermediate  steps  or  conditions, 
or  whatever  the  apparatus.  Therefore,  when  a 
given  quantity  of  water  at  a  given  temperature 
has  been  made  into  steam  at  a  given  temperature, 
a  certain  definite  work  has  been  done,  and  a  cer- 
tain amount  of  energy  expended,  from  whatever 
the  heat  may  have  been  obtained,  or  whatever 
boiler  may  have  been  employed  for  the  purpose. 

A  pound  of  coal  or  any  other  fuel  has  a  defi- 
nite heat  producing  capacity,  and  is  capable  of 
evaporating  a  definite  quantity  of  water  under 
given  conditions.  That  is  the  limit  beyond  which 
even  perfection  cannot  go,  and  yet  I  have  known, 
and  doubtless  you  have  heard  of,  cases  where 
inventors  have  claimed,  and  so-called  engineers 
have  certified  to,  much  higher  results. 

The  first  step  in  generating  steam  is  in  burning 
the  fuel  to  the  best  advantage.  A  pound  of  car- 
bon will  generate  14,500  British  thermal  units, 
during  combustion  into  carbonic  dioxide,  and 
this  will  be  the  same,  whatever  the  temperature 
or  the  rapidity  at  which  the  combustion  may 
take  place.  If  possible,  we  might  oxidize  it  at 
as  slow  a  rate  as  that  with  which  iron  rusts  or 
wood  rots  in  the  open  air,  or  we  might  burn  it 
with  the  rapidity  of  gunpowder,  a  ton  in  a  sec- 
ond, yet  the  total  heat  generated  would  be  pre- 
cisely the  same.  Again,  we  may  keep  the  tem- 
perature down  to  the  lowest  point  at  which 
combustion  can  take  place,  by  bringing  large 
bodies  of  air  in  contact  with  it,  or  otherwise,  or 
we  may  supply  it  with  just  the  right  quantity  of 
pure  oxygen,  and  burn  it  at  a  temperature  ap- 
proaching that  of  dissociation,  and  still  the  heat 
units  given  off  will  be  neither  more  nor  less.  It 
follows,  therefore,  that  great  latitude  in  the  man- 
ner or  rapidity  of  combustion  may  be  taken 
without  affecting  the  quantity  of  heat  generated. 


But  in  practice  it  is  found  that  other  consider- 
ations limit  this  latitude,  and  that  there  are 
certain  conditions  necessary  in  order  to  get  the 
most  available  heat  from  a  pound  of  coal.  There 
are  three  ways,  and  only  three,  in  which  the  heat 
developed  by  the  combustion  of  coal  in  a  steam 
boiler  furnace  may  be  expended. 

First,  and  principally,  it  should  be  conveyed 
to  the  water  in  the  boiler,  and  be  utilized  in  the 
production  of  steam.  To  be  perfect,  a  boiler 
should  so  utilize  all  the  heat  of  combustion,  but 
there  are  no  perfect  boilers. 

Second. — A  portion  of  the  heat  of  combustion 
is  conveyed  up  the  chimney  in  the  waste  gases. 
This  is  in  proportion  to  the  weight  of  the  gases, 
and  the  difference  between  their  temperature 
and  that  of  the  air  and  coal  before  they  entered 
the  fire. 

Third. — Another  portion  is  dissipated  by  radi- 
ation from  the  sides  of  the  furnace.  In  a  stove 
the  heat  is  all  used  in  these  latter  two  ways, 
either  it  goes  off  through  the  chimney  or  is  radi- 
ated into  the  surrounding  space.  It  is  one  of 
the  principal  problems  of  boiler  engineering  to 
render  the  amount  of  heat  thus  lost  as  small  as 
possible. 

The  loss  from  radiation  is  in  proportion  to  the 
amount  of  surface,  its  nature,  its  temperature, 
and  the  time  it  is  exposed.  This  loss  can  be 
almost  entirely  eliminated  by  thick  walls  and  a 
smooth  white  or  polished  surface,  but  its  amount 
is  ordinarily  so  small  that  these  extraordinary 
precautions  do  not  pay  in  practice. 

It  is  evident  that  the  temperature  of  the  escap- 
ing gases  cannot  be  brought  below  that  of  the 
absorbing  surfaces,  while  it  may  be  much  greater 
even  to  that  of  the  fire.  This  is  supposing  that 
all  of  the  escaping  gases  have  passed  through 
the  fire.  In  case  air  is  allowed  to  leak  into  the 
flues,  and  mingle  with  the  gases  after  they  have 
left  the  heating  surfaces,  the  temperature  may 
be  brought  down  to  almost  any  point  above 
that  of  the  atmosphere,  but  without  any  reduction 
in  the  amount  of  heat  v^^asted.  It  is  in  this  way 
that  those  low  chimney  temperatures  are  some- 
times attained  which  pass  for  proof  of  economy 
with  the  unobserving.  All  surplus  air  admitted 
to  the  fire,  or  to  the  gases  before  they  leave  the 
heating  surfaces,  increases  the  losses. 

We  are  now  prepared  to  see  why  and  how 
the  temperature  and  the  rapidity  of  combustion 
in  the  boiler  furnace  affect  the  economy,  and 
that  though  the  amount  of  heat  developed  may 
be  the  same,  the  heat  available  for  the  generation 
of  steam  may  be  much  less  with  one  rate  or 
temperature  of  combustion  than  another. 

Assuming  that  there  is  no  air  passing  up  the 


17 


4--^ 


chimney  ollur  lli;m  tlial  \\iii(  li  has  passi'd 
llu'oui;h  thi-  liic,  lliu  lii<;liL'r  llic  lemperaliirc  of 
the  lux-  ami  the  lower  that  of  the  escajjini;- 
<;ases  the  better  the  ea)iioniy,  for  the  losses  l)y 
the  chimney  teases  will  bear  the  same  proportion 
to  the  heat  .generated  by  the  combustion  as  the 
temperatiue  of  those  gases  bears  to  the  temper- 
ature of  the  lire.  That  is  to  say,  if  the  temperature 
of  the  fire  is  2,500°  and  that  of  the  chimney  gases 
500°  above  that  of  the  atmosphere,  the  loss  by 
the  chimney  will  be  ^/jf^f  =  20  per  cent.  There- 
fore, as  the  escaping  gases  cannot  be  brought 
below  the  temperature  of  the  absorbing  surface, 
which  is  practically  a  fixed  quantity,  the  tem- 
perature of  the  fire  must  be  high  in  order  to 
secure  good  economy. 

The  losses  by  radiation  being  practically  pro- 
portioned to  the  time  occupied,  the  more  coal 
burned  in  a  given  furnace  in  a  given  time,  the  less 
will  be  the  proportionate  loss  from  that  cause. 

It  therefore  follows  that  we  should  burn  our 
coal  rapidly  and  at  a  high  temperature,  to  secure 
the  best  available  economy. 


CIRCULATION    OF    WATER    IN    STEAM   BOILERS. 

[From  a  lecture  by  George  H.  Babcock,  delivered  at 
Cornell  University,  February,  1890.] 

You  have  all  noticed  a  kettle  of  water  boiling 
over  the  fire,  the  fluid  rising  somewhat  tumultu- 
ously  around  the  edges  of  the  vessel,  and  tum- 
bling toward  the  center,  where  it  descends. 
Similar  currents  are  in  action  while  the  water  is 
simply  being  heated,  but  they  are  not  percepti- 
ble unless  there  are  floating  particles  in  the 
liquid.  These  currents  are  caused  by  the  joint 
action  of  the  added  temperature  and  two  or 
more  qualities  which  the  water  possesses. 

1.  Water,  in  common  with  most  other  sub- 
stances, expands  when  heated  ;  a  statement, 
however,  strictly  true  only  when  referred  to  a 
temperature  above  39°  F.  or  4°  C,  but  as  in  the 
making  of  steam  we  rarely  have  to  do  with  tem- 
peratures so  low  as  that,  we  may,  for  our  present 
purposes,  ignore  that  exception. 

2.  Water  is  practically  a  non-conductor  of 
heat,  though  not  entirely  so.  If  ice-cold  water 
was  kept  boiling  at  the  surface  the  heat  would 
not  penetrate  sufficiently  to  begin  melting  ice  at 
a  depth  of  three  inches  in  less  than  about  two 
hours.  As,  therefore,  the  heated  water  cannot 
impart  its  heat  to  its  neighboring  particles,  it 
remains  expanded  and  rises  by  its  levity,  while 
colder  portions  come  to  be  heated  in  turn,  thus 
setting  up  currents  in  the  fluid. 

Now,  when  all  the  water  has  been  heated  to 
the  boiling  point  corresponding  to  the  pressure 
to  which  it  is  subjected,  each  added  unit  of  heat 


^ 

'.%»an 

i 

t 

1 

HHI 

i||lil" 

@Se9 

^^ 

^ 

Jb 

--'^     \\ 

V^ 

^  "^ 

^ZS^A'-J: 

mi^il^:- 

Fig 


(•()n\(Tls  a  |)i)rliiin,  alxmt  seven  grains  in  weight, 
into  vapor,  greatly  increasing  its  volume;  and 
the  mingled  steam  and  water  rises  more  rapidly 
still,  producing  el)ulIition  such  as  we  have  no- 
ticed in  the  kettle.  So  long  as  the  quantity  of 
heat  added  to  the  contents  of  the  kettle  contin- 
ues practically  constant,  the  conditions  remain 
similar  to  those  we 
noticed  at  first,  a 
tumultuous  lifting 
of  the  water  around 
the  edges,  flowing 
toward  the  center 
and  thence  down- 
ward ;  if,  however, 
the  fire  be  quick- 
ened, the  upward 
currents  interfere 
with  the  downward 
and  the  kettle  boils 
over.  (Fig.  i.  j 
If  now  we  put  in 
the  kettle  a  vessel  somewhat  smaller  (Fig.  2) 
with  a  hole  in  the  bottom  and  supported  at  a 
proper  distance  from  the  side  so  as  to  separate 
the  upward  from  the  downward  currents,  we  can 
force  the  fires  to  a  very  much  greater  extent- 
without  causing  the  kettle  to  boil  over,  and 
when  we  place  a  deflecting  plate  so  as  to  guide 
the  rising  column  toward  the  center  it  will  be 
almost  impossible 
to  produce  that  ef- 
fect. This  is  the 
invention  of  Per- 
kins in  1 83 1  and 
forms  the  basis  of 
very  many  of  the 
arrangements  for 
producing  free  cir- 
culation of  the  water 
in  boilers  which 
have  been  made 
since  that  time.  It 
consists  in  dividing 
the  currents  so  that 


Fig.  2: 

they  will  not  interfere  each  wdth  the  other. 
But  what  is  the  object  of  facilitating  the  circu- 
lation of  water  in  boilers?  "Why  may  we  not 
safely  leave  this  to  the  unassisted  action  of  na- 
ture as  we  do  in  culinary  operations  ?  We  may, 
if  we  do  not  care  for  the  three  most  important 
aims  in  steam-boiler  construction,  namely,  effi- 
ciency, durability,  and  safety,  each  of  which  is 
more  or  less  dependent  upon  a  proper  circula- 
tion of  the  water.  As  for  efficiency,  we  have 
seen  one  proof  in  our  kettle.  When  we  provided 
means  to  preserve  the  circulation,  we  found  that 


■^ 


I 


^ 


chimiie'v  oIIht  lli.in  lli.il  uliiili  li.ts  ]),'issc(l 
throui;h  tin-  lire,  llic  lii,L;lHi'  the  tiiu|)cnitiitv  of 
llie  fire  and  tlie-  lower  tlial  of  tin-  esrai)iniL;- 
gases  the  better  the  economy,  for  iIr'  losses  by 
tlie  chinniey  <;ases  will  bear  the  same  proportion 
to  the  heat  generated  by  the  combustion  as  the 
lemperatme  of  those  gases  bears  to  the  temi)er- 
ature  of  the  fire.  That  is  to  say,  if  the  temperature 
of  the  fire  is  2,500°  and  that  of  the  chimney  gases 
500°  above  that  of  the  atmosphere,  the  loss  by 
the  chimney  will  be  ^iPs'=2o  per  cent.  There- 
fore, as  the  escaping  gases  cannot  be  brought 
below  the  temperature  of  the  absorbing  surface, 
which  is  practically  a  fixed  quantity,  the  tem- 
perature of  the  fire  must  be  high  in  order  to 
secure  good  economy. 

The  losses  by  radiation  being  practically  pro- 
portioned to  the  time  occupied,  the  more  coal 
burned  in  a  given  furnace  in  a  given  time,  the  less 
will  be  the  proportionate  loss  from  that  cause. 

It  therefore  follows  that  we  should  burn  our 
coal  rapidly  and  at  a  high  temperature,  to  secure 
the  best  a\^ailable  economy. 


CIRCULATION    OF    WATER    IN    STEAM   BOILERS. 

[From  a  lecture  by  George  H.  Babcock,  delivered  at 
Cornell  University,  February,  iSgc] 

You  have  all  noticed  a  kettle  of  water  boiling 
over  the  fire,  the  fluid  rising  somewhat  tumultu- 
ously  around  the  edges  of  the  vessel,  and  tum- 
bling toward  the  center,  where  it  descends. 
Similar  currents  are  in  action  while  the  water  is 
simply  being  heated,  but  they  are  not  percepti- 
ble unless  there  are  floating  particles  in  the 
liquid.  These  currents  are  caused  by  the  joint 
action  of  the  added  temperature  and  two  or 
more  qualities  which  the  water  possesses. 

1.  Water,  in  common  with  most  other  sub- 
stances, expands  when  heated  ;  a  statement, 
however,  strictly  true  only  when  referred  to  a 
temperature  above  39°  F.  or  4°  C,  but  as  in  the 
making  of  steam  we  rarely  have  to  do  with  tem- 
peratures so  low  as  that,  we  may,  for  our  present 
purposes,  ignore  that  exception. 

2.  Water  is  practically  a  non-conductor  of 
heat,  though  not  entirely  so.  If  ice-cold  water 
was  kept  boiling  at  the  surface  the  heat  would 
not  penetrate  sufficiently  to  begin  melting  ice  at 
a  depth  of  three  inches  in  less  than  about  two 
hours.  As,  therefore,  the  heated  water  cannot 
impart  its  heat  to  its  neighboring  particles,  it 
remains  expanded  and  rises  by  its  levity,  while 
colder  portions  come  to  be  heated  in  turn,  thus 
setting  up  currents  in  the  fluid. 

Now,  when  all  the  water  has  been  heated  to 
the  boiling  point  corresponding  to  the  pressure 
to  which  it  is  subjected,  each  added  unit  of  heat 


converts  a  portion,  alj(jut  seven  grains  in  weight, 
into  \apor,  greatly  increasing  its  volume;  and 
the  mingled  steam  and  water  rises  more  rapidly 
still,  producing  el)ullition  such  as  we  have  no- 
ticed in  the  kettle.  .So  long  as  the  quantity  of 
heat  added  tcj  the  contents  of  the  kettle  contin- 
ues practically  constant,  the  conditions  remain 
similar  to  those  we 
noticed  at  first,  a 
tumultuous  lifting 
of  the  water  around 
the  edges,  flowing 
toward  the  center 
and  thence  down- 
ward ;  if,  however, 
the  fire  be  cjuick- 
ened,  the  upward 
currents  interfere 
with  the  downward 
and  the  kettle  boils 
over.  (  Fig.  i. ) 
If  now  we  put  in 
the  kettle  a  vessel  somewhat  smaller  (Fig.  2) 
with  a  hole  in  the  bottom  and  supported  at  a 
proper  distance  from  the  side  so  as  to  separate 
the  upward  from  the  downward  currents,  we  can 
force  the  fires  to  a  very  much  greater  extent 
without  causing  the  kettle  to  boil  over,  and 
when  we  place  a  deflecting  plate  so  as  to  guide 
the  rising  column  toward  the  cpntp-r  it  will  be 
almost  impossible 
to  produce  that  ef-  >^,^^, 
feet.  This  is  the 
invention  of  Per- 
kins in  1831  and 
forms  the  basis  of 
very  many  of  the 
arrangements  for 
producing  free  cir- 
culation of  the  water 
in  boilers  which 
have  been  made 
since  that  time.  It 
consists  in  dividing 
the  currents  so  that  ^ig-  -• 

they  will  not  interfere  each  with  the  other. 
But  what  is  the  object  of  facilitating  the  circu- 
lation of  water  in  boilers?  A\Tiy  may  we  not 
safely  leave  this  to  the  unassisted  action  of  na- 
ture as  we  do  in  culinarj-  operations  ?  We  may, 
if  we  do  not  care  for  the  three  most  important 
aims  in  steam-boiler  construction,  namely,  eflfi- 
cienc}^,  durability,  and  safet\-,  each  of  which  is 
more  or  less  dependent  upon  a  proper  circula- 
tion of  the  w^ater.  As  for  efficiency,  we  have 
seen  one  proof  in  our  kettle.  A\Tien  we  provided 
means  to  preserve  the  circulation,  we  found  that 


19 


■n^ 


•^ 


■^ 


we  could  carry  a  hotter  fire  and  boil  away  tlie 
water  much  more  rapidly  than  before.  It  is  the 
same  in  a  steam  boiler.  And  we  also  noticed 
that  when  there  was  nothing  but  the  unassisted 
circulation,  the  rising  steam  carried  away  so  much 
water  in  the  form  of  foam  that  the  kettle  boiled 
over,  but  when  the  currents  were  separated  and 
an  unimpeded  circuit  was  established,  this 
ceased,  and  a  much  larger  supply  of  steam  was 
delivered  in  a  comparatively  dry  state.  Thus, 
circulation  increases  the  efficiency  in  two  ways  : 
it  adds  to  the  ability  to  take  up  the  heat,  and 
decreases  the  liability  to  waste  that  heat  by  what 
is  technically  known  as  priming.  There  is  yet 
another  way  in  which,  incidentally,  circulation 
increases  efficiency  of  surface,  and  that  is  by 
preventing  in  a  greater  or  less  degree  the  for- 
mation of  deposits  thereon.  Most  waters  contain 
some  impurity  which,  when  the  water  is  evapo- 
rated, remains  to  incrust  the  surface  of  the  vessel. 
This  incrustation  becomes  very  serious  some- 
times, so  much  so  as  to  almost  entirely  prevent 
the  transmission  of  heat  from  the  metal  to  the 
water.  It  is  said  that  an  incrustation  of  only  yi 
inch  will  cause  a  loss  of  25  per  cent,  in  efficiency, 
and  that  is  probably  within  the  truth  in  many 
cases.  Circulation  of  water  will  not  prevent  in- 
crustation altogether,  but  it  lessens  the  amount 
in  all  waters,  and  almost  entirely  so  in  some,  thus 
adding  greatly  to  the  efficiency  of  the  surface. 

A  second  advantage  to  be  obtained  through 
circulation  is  durability  of  the  boiler.  This  it 
secures  mainly  by  keeping  all  parts  at  a  nearly 
uniform  temperature.  The  way  to  secure  the 
greatest  freedom  from  unequal  strains  in  a  boiler 
is  to  provide  for  such  a  circulation  of  the  water 
as  will  insure  the  same  temperature  in  all  parts. 
3.  Safety  follows  in  the  wake  of  durability, 
because  a  boiler  which  is  not  subject  to  unequal 
strains  of  expansion  and  contraction  is  not  only 
less  liable  to  ordinary  repairs,  but  also  to  rup- 
ture and  disastrous  explosion.  By  far  the  most 
_^_  prolific  cause   of  explosions  is 

2j<^    ~  this  same  strain  from   unequal 

i^^  expansions. 

-^^'^  '  "  '  Having  thus  briefly  looked  at 

^^  --  the  advantages  of  circulation  of 
water  in  steam  boilers,  let  us  see 
what  are  the  best  means  of  secur- 
ing it  under  the  most  efficient 
conditions.  We  have  seen  in  our 
kettle  that  one  essential  point 
was  that  the  currents  should  be 
kept  from  interfering  with  each 
other.  If  we  could  look  into  an 
ordinary  return  tubular  boiler 
Fig.  3.  when  steaming,  we  should  see  a 


I  i| 


curious  commotion  of  currents  rusiiing  hither  and 
thither,and  shifting  continuallyasoneortheother 
contending  force  gained  a  momentary  mastery. 
The  principal  upward  currents  would  be  found  at 
the  two  ends,  one  over  the  fire  and  the  other  over 
the  first  foot  or  so  of  the  tubes.  Between  these, 
the  downward  currents  struggle  against  the  rising 
currents  of  steam  and  water.  At  a  sudden  de- 
mand for  steam,  or  on  the  lifting  of  the  safety 
valve,  the  pressure  being  slightly  reduced,  the 
water  jumps  up  in  jets  at  every  portion  of  the  sur- 
face, being  lifted  by  the  sudden  generation  of 
steam  throughout  the  body  of  water.  You  have 
seen  the  effect  of  this  sudden  generation  of  steam 
in  the  well-known  experiment  with  a  Florence 
flask,  to  which  a  cold  application  is  made  while 
boiling  water  under  pressure  is  within.  You 
have  also  witnessed  the  geyser-like  action  when 
water  is  boiled  in  a  test  tube  held  vertically 
over  a  lamp  (Fig.  3). 
If  now  we  take  a  U 
tube  depending  from  a 
vessel  of  water  ( Fig.  4 ) 
and  apply  the  lamp  to 
one  leg  a  circulation  is 
at  once  set  up  within 
it,  and  no  such  spas- 
modic action  can  be 
produced.  This  U  tube 
is  the  representative  of 
the  true  method  of  cir- 
culation within  a  water 
tube  boiler  properly 
constructed.  We  can, 
for  the  purpose  of  se- 
curing more  heating 
surface,  extend  the 
heated  leg  into  a  long 
incline  (Fig.  5),  when 
we  have  the  well- 
known  inclined-tube 
generator.  Now,  by 
adding  other  tubes,  we 
may  further  increase 
the  heating  surface  (Fig.  6),  while  it  will  still  be 
the  U  tube  in  effect  and  action.  In  such  a  con- 
struction the  circulation  is  a  function  of  the  dif- 
ference in  density  of  the  two  columns.  Its 
velocity  is  measured  by  the  well-known  Torri- 
cellian formula,  V  =  1/2^/;,  or,  approximately, 
V  =  8  1/  /i,  h  being  measured  in  terms  of  the 
lighter  fluid.  This  velocity  will  increase  until 
the  rising  column  becomes  all  steam,  but  the 
quantity  or  weight  circulated  will  attain  a  maxi- 
mum when  the  density  of  the  mingled  steam  and 
water  in  the  rising  column  becomes  one-half  that 
of  the  solid  water  in  the   descending  column, 


Fig.  5- 


21 


■^ 


which  is  nearly  coincident  witli  the  condition  of 
half  steam  and  half  water,  the  weight  of  the 
steam  being  very  slight  compared  to  that  of  the 
water. 


It  becomes  easy  by  this  rule  to  determine  the 
circulation  in  any  given  boiler  built  on  this  prin- 
ciple, provided  the  construction  is  such  as  to 
permit  a  free  flow  of  the  water.  Of  course, 
every  bend  detracts  a  little  and  something  is 
lost  in  getting  up  the  velocity,  but  when  the 
boiler  is  well  arranged  and  proportioned  these 
retardations  ai^e  slight. 

Let  us  take  for  example  one  of  the  240-horse 
power  Babcock  &  Wilcox  boilers  here  in  the 
University.  The  height  of  the  columns  maj^  be 
taken  as  four  and  one-half  feet,  measuring  from 
the  surface  of  the  water  to  about  the  center  of 
the  bundle  of  tubes  over  the  fire,  and  the  head 
would  be  equal  to  this  height  at  the  maximum 
of  circulation.  We  should,  therefore,  have  a 
velocity  of  8  V A}2  =  16.97,  say  17  feet  per  sec- 
ond. There  are  in  this  boiler  fourteen  sections, 
each  having  a  4^''  tube  opening  into  the  drum, 
the  area  of  which  (inside)  is  11  square  inches, 
the  14  aggregating  154  square  inches,  or  1.07 
square  feet.  This  multiplied  by  the  velocity, 
16.97  feet,  gives  18.16  cubic  feet  mingled  steam 
and  water  discharged  per  second,  one  half  of 
which,  or  9.08  cubic  feet,  is  steam.  Assuming 
this  steam  to  be  at  100  pounds  gauge  pressure, 
it  will  weigh  0.258  pound  per  cubic  foot. 
Hence,  2.34  pounds  of  steam  will  be  discharged 
per  second,  and  8,433  pounds  per  hour.  Divid- 
ing this  by  30,  the  number  of  pounds  represent- 
ing a  boiler  horse  power,  we  get  281.  i  horse 
power,  about  17  per  cent,  in  excess  of  the  rated 
power  of  the  boiler.  The  water  at  the  temper- 
ature of  steam  at  100  pounds  pressure  weighs  56 
pounds  per  cubic  foot,  and  the  steam  0.258 
pound,  so  that  the  steam  forms  but  olg-  part  of 
the  mixture  by  weight,  and  consequent^  each 
particle  of  water  will  make  218  circuits  before 
being  evaporated  when  working  at  this  capacity, 


and  circulating  the  maximum  weight  of  water 
through  the  tubes. 

It  is  evident  that  at  the  highest  possible  veloc- 
ity of  exit  from  the  generating  tubes,  nothing 
but  steam  will  be  delivered  and  there  will  be  no 
circulation  of  water  except  to  supply  the  place 
of  that  evaporated.  Let  us  see  at  what  rate  of 
steaming  this  would  occur  with  the  boiler  under 
consideration.  We  shall  have  a  column  of 
steam,  say  four  feet  high  on  one  side  and  an 
equal  column  of  water  on  the  other.  Assuming, 
as  before,  the  steam  at  100  pounds  and  the  water 
at  same  temperature,  we  will  have  a  head  of 
866  feet  of  steam  and  an  issuing  velocity  of 
235.5  feet  per  second.  This  multiplied  by  1.07 
square  feet  of  opening  and  3,600  seconds  in  an 
hour  gives  234,043  pounds  of  steam,  which, 
though  only  one-eighth  the  weight  of  mingled 
steam  and  water  delivered  at  the  maximum, 
gives  us  7,801  horse  power,  ox  over  32  times  the 
rated  power  of  the  boiler.  Of  course,  this  is  far 
beyond  any  possibility  of  attainment,  so  that  it 
may  be  set  down  as  certain  that  this  boiler  can- 
not be  forced  to  a  point  where  there  will  not  be 
an  efficient  circulation  of  the  water.  By  the 
same  method  of  calculation  it  may  be  shown 
that  when  forced  to  double  its  rated  power,  a 
point  rarely  expected  to  be  reached  in  practice, 
about  two-thirds  the  volume  of  mixture  of 
steam  and  water  delivered  into  the  drum  will 
be  steam,  and  that  the  water  will  make  no  cir- 
cuits while  being  evaporated.  Also  that  when 
worked  at  only  about  one- quarter  its  rated  ca- 
pacity, one-fifth  of  the  volume  will  be  steam  and 
the  water  will  make  the  rounds  870  times  be- 
fore it  becomes  steam.  You  will  thus  see  that 
in  the  proportions  adopted  in  this  boiler  there 
is  provision  for  perfect  circulation  under  all  the 
possible  conditions  of  practice. 

In  designing  boilers 
of  this  style  it  is  neces-  "  ^^^  -  _  ,_  ^,  ^ 

sary  to  guard  against  '""  ""'     "" 

having  the  uptake  at 
the  upper  end  of  the 
tubes  too  large,  for  if 
sufficiently  large  to  al- 
low downward  cur- 
rents therein,  the 
whole  effect  of  the  ris- 
ing column  in  increas-  ■:ZZ,:- 
ing  the  circulation  in  ^'S-  7- 
the  tubes  is  nullified  (Fig.  7).  This  will  readily 
be  seen  if  we  consider  the  uptake  very  large 
— when  the  only  head  producing  circulation  in 
the  tubes  will  be  that  due  to  the  inclination  of 
each  tube  taken  by  itself.  This  objection  is 
only  overcome  when  the  uptake  is  so  small  as  to 


^ 


23 


•^ 


^ 


Babcock  &  Wilcox  Boilers  at  Baldwin  Locomotive  Works,  Philadelphia,  Pa.       3464  H.P.  now  in  use. 


»f4- 


be  entirely 'filled  with  the  ascending  cuirent  of 
mingled  steam  and  water.  It  is  also  necessary 
that  this  uptake  should  be  practically  direct,  and 
it  should  not  be  composed  of  frequent  enlarge- 
ments and  contractions.  Take,  for  instance,  a 
boiler  well  known  in  Europe,  copied  and  sold 
here  under  another  name.  It  is  made  up  of  in- 
clined tubes  secured  by  pairs  into  boxes  at  the 
ends,  which  boxes  are  made  to  communicate 
with  each  other  by  return  bends  opposite  the 
ends  of  the  tubes.  These  boxes  and  return 
bends  form  an  irregular  uptake,  whereby  the 
steam  is  expected  to  rise  to  a  reservoir  above. 
You  will  notice  (Fig.  8)  that  the  upward  current 


Fig.  S.  [Developed  to  show  Circulation.] 

of  steam  and  water  in  the  return  bend  meets  and 
directly  antagonizes  the  upward  current  in  the 
adjoining  tube.  Only  one  result  can  follow. 
If  their  velocities  are  equal,  the  momentum  of 
both  will  be  neutralized  and  all  circulation 
stopped,  or,  if  one  be  stronger,  it  will  cause  a 
back  flow  in  the  other  by  the  amount  of  differ- 
ence in  force,  with  practically  the  same  result. 

In  a  well  known  boiler,  many  of  which  were 
sold,  but  of  which  none  are  now  made  and  very 
few  are  still  in  use,, the  inventor  claimed  that 
the  return  bends  and  small  openings  against 
the  tubes  were  for  the  purpose  of  "restricting 
^^  the    circulation,"    and 

no  doubt  they  per- 
formed well  that  office ; 
but  excepting  for  the 
smallness  of  the  open- 
ings they  were  not  as 
efficient  for  that  pur- 
pose as  the  arrange- 
ment shown  in  Fig.  8. 
Another  form  of 
boiler,  first  invented 
by  Clarke  or  Crawford, 
and  lately  revived,  has 
the  uptake  made  of  box- 
es into  which  a  number, 


generally  from  two  to  four,  tubes  are  expanded, 
the  boxes  being  connected  together  by  nipples 
(Fig.  9).  It  is  a  well-known  fact  that  where  a 
fluid  flows  through  a  conduit  which  enlarges  and 
then  contracts,  the  velocity  is  lost  to  a  greater  or 
less  extent  at  the  enlargements,  and  has  to  be 
gotten  up  again  at  the  contractions  each  time, 
with  a  corresponding  loss  of  head.  The  same 
thing  occurs  in  the  construction  shown  in  Fig.  9. 
The  enlargements  and  contractions  quite  destroy 
the  head  and  practically  overcome  the  tendency 
of  the  water  to  circulate. 

A  horizontal  tube  stopped  at  one  end,  as  shown 
in  Fig.  10,  can  have  no  proper  circulation  within 
it.  If  moderately  driven,  the  water  may  struggle 
in  against  the  issuing  steam  sufficiently  to  keep 
the  surfaces  covered,  but  a  slight  degree  of  forc- 
ing will  cause  it  to  act  like  the  test  tube  in  Fig. 
3,  and  the  more  there  are  of  them  in  a  given 
boiler  the  more  spasmodic  will  be  its  working. 

The  experiment  with  our  kettle  ( Fig.  2 )  gives 
the  clue  to  the  best  means  of  promoting  circula- 
tion in  ordinary  shell  boilers.  Steenstrup  or 
"  Martin  "  and  "  Galloway  "  water  tubes  placed 
in  such  boilers  also  assist  in  directing  the  circu- 
lation therein,  but  it  is  almost  impossible  to  pro- 
duce in  shell  boilers,  by  any  means,  the  circula- 
tion of  all  the  water  in  one  continuous  round, 
such  as  marks  the  well-constnu^ted  water-tube 
boiler. 


Fig.  lo. 

As  I  have  before  remarked,  provision  for  a 
proper  circulation  of  water  has  been  almost  uni- 
versally ignored  in  designing  steam  boilers, 
sometimes  to  the  great  damage  of  the  owner,  but 
oftener  to  the  jeopardy  of  the  lives  of  those  who 
are  employed  to  run  them.  The  noted  case  of 
the  Montana  and  her  sister  ship,  where  some 
1300,000  was  thr-own  away  in  trying  an  experi- 
ment which  a  proper  consideration  of  this  sub- 
ject would  have  avoided,  is  a  case  in  point ;  but 
who  shall  count  the  cost  of  life  and  treasure  not, 
perhaps,  directly  traceable  to,  but,  nevertheless, 
due  entirely  to  such  neglect  in  design  and  con- 
struction of  the  thousands  of  boilers  in  which 
this  necessary  element  has  been  ignored? 


>"4- 


25 


BRIEF  HISTORY  OF  WATER -TUBE  BOILERS* 

Water-tube  boilers  are  not  new.  From  the 
earliest  days  of  the  steam  engine,  there  have 
been  those  who  recog- 
nized their  advantages. 
The  first  water-tube  boiler 
recorded  was  made  by  a 

contemporary    of    Watt, 

William  Blakey,  in  1766. 
He  arranged  several  tubes 
in  a  furnace,  alternately 
inclined  at  opposite  an- 
gles, and  connected  at 
their  contiguous  ends  by 
smaller  pipes.  But  the 
first  successful  user  of 
such  boilers  was  James 
Rumsay,  an  American 
inventor,  celebrated  for 
his  early  experiments  in 
steam  navigation,  and 
who  may  be  truly  classed 
as  the  originator  of  the 
water-tube  boiler,  as  now 
known.  In  1788  he  pat- 
ented, in  England,  several 


combination  of  small  tubes,  connected  at  one 
end  to  a  reservoir,  was  the  invention  of  another 
American,  John  Cox  Stevens,  in  1805. 


Joseph  Eve,  1825. 


Stevens,  1805. 

forms  of  boilers,  among  them, 
one  having  a  fire-box  with  flat 
water -sides  and  top,  across 
which  were  horizontal  water- 
tubes  connecting  with  the  water 
spaces.  Another  was  a  coiled 
tube  within  a  cylindrical  fire-box, 
connecting  at  its  two  ends  with 
the  annular  surrounding  water 
space.  This  was  the  first  of  the 
"coil  boilers."  Another  form 
in  the  same  patent  was  the  verti- 
cal tubular  boiler,  as  at  present 
made. 
The  first  boiler  made    of    a 


This  boiler  was  actually  em- 
ployed to  drive  a  steamboat  on  the 
Hudson  River,  but  like  all  the 
"porcupine"  boilers  of  which  it 
was  the  first,  it  did  not  have  the 
elements  of  a  continued  success. 

About  the  same  time.  Wolf,  the 
inventor  of  compound  engines, 
made,  a  boiler  of  large  horizontal 
tubes,  laid  across  the  furnace  and 
connected  at  the  ends  to  a  longi- 
tudinal drum  above.  The  first 
purely  sectional  water-tube  boiler 


*  See  discussion  by  Geo.  H.  Babcock,  of 
Sterling's  paper  on  "  Water-tube  and  Shell 
Boilers,"  in  Trans.  Avi.  Society  of 
Mechanical  Engineers,  Vol.  VI.,  p.  6oi. 


Gurney,  1826. 


27 


■^ 


was  made  by  Julius  Griffith,  in  1S21,  who  used  a 
number  of  horizontal  water-tubes  connected  to 
vertical  side  pipes,  which  were  in  turn  connected 
to  horizontal  gathering  pipes,  and  these  to  a 
steam  drum.  The  first  sectional  water-tube 
boiler,  with  a  well-defined  circulation,  was  made 
by  Joseph  Eve,  in  1S25.  His  sections  were  com- 
posed of  small  tubes  slightly  double  curved  but 
practically  vertical,  fixed  in  hori- 
zontal headers,  which  were  in  turn 
connected  to  a  steam  space  above 
and  water  space  below  formed  of 
larger  pipes,  and  connected  by 
outside  pipes  so  as  to  secure  a 
circulation  of  the  water  up  through 
the  sections  and  down  the  external 
pipes.  The  same  year 
John  M' Curdy,  of  New 
York,  made  a  "Duplex 
Steam  Generator,"  of 
"  tubes  of  wrought 
or  cast-iron  or  other 
material ' '  arranged 
in  several  horizontal 
rows,  connected  to- 
gether alternately  """  s'^*'-' 
front  and  rear  by  re- 
turn bends.  In  1826,  Goldsworthy  Gurney 
made  a  number  of  boilers  which  he  used  on 
his  steam  carriages,  consisting  of  a  series  of 
small  tubes  bent  into  the  shape  of  a  U  laid  edge- 
wise, which  connected  top  and  bottom  with  large 
horizontal  pipes.     These  latter  were  united  by 


necting  them,  through  which  were  fire-tubes  ex- 
tending through  the  horizontal  connections,  with 
nuts  upon  them  to  bind  the  parts  together  and 
make  the  joints,  suggesting  some  recent  patents. 
The  first  person  to  use  inclined  water-tubes 
connecting  water  spaces  front  and  rear  with  a 
steam  space  above,  was  Stephen  Wilcox  in  1856, 
and  the  first  to  make  such  inclined  tubes  into  a 


'-'^yyyyyyy^^y^y^-^y^yyyyyyyyyy^^^^ 


Wilcox,  1856. 

vertical  pipes  to  permit  of  circulation,  and  also 
connected  to  a  vertical  cylinder  forming  the 
steam  and  water  reservoirs.  In  1828,  Paul 
Steenstrup  made  the  first  shell  boiler  with  ver- 
tical water-tubes  in  the  large  flues,  similar  to 
what  is  known  as  the  "  Martin,"  and  suggesting 
the  "  Galloway." 

The  first  water-tube  boiler  having  fire-tubes 
within  water-tubes  was  made  in  1830,  by  Sum- 
mers &  Ogle.  Horizontal  connections  at  top  and 
bottom  had  a  series  of  vertical  water-tubes  con- 


Twibill,  1865. 

sectional  form  was  one  Twibill  in  1865.  He 
used  wrought-iron  tubes  connected  front  and 
rear  by  intermediate  connections  with  stand 
pipes,  which  carried  the  steam  to  a  horizontal 
cross-drum  at  the  top,  the  entrained  water  being 
carried  back  to  the  rear. 

Time  would  fail  to  tell  of  Clark,  and 
Perkins,  and  Moore  (English),  and 
McDowell,  and  Alban,  and  Craddock, 
and  the  host  of  others  who  have  tried  to 
make  water-tube  boilers,  and  have  not 
made  practical  successes,  because  of  the 
difficulties  of  the  problem. 

Why  are  not  water-tube  boilers  in 
more  general  use,  compared  with  shell 
boilers  ?  is  asked.  Because  they  require 
a  high  class  of  engineering  to  make  them 
successful.  The  plain  cylinder  is  an 
easy  thing  to  make.  It  requires  little 
skill  to  rivet  sheets  into  a  cylinder,  build  a 
fire  under  it  and  call  it  a  boiler ;  and  because 
it  is  easy  and  anyone  can  make  such  a  boiler — 
because  it  requires  no  special  engineering — they 
have  been  made,  and  are  still  made,  to  a  very 
large  extent.  The  water-tube  boiler,  on  the 
other  hand,  requires  much  more  skill  in  order 
to  make  it  successful.  This  is  proved  by  the 
great  number  of  failures  in  attempts  to  make 
water-tube  boilers,  some  of  which  are  referred 
to  in  the  paper  under  discussion. 


^ 


29 


■^ 


EVOLUTION    OF    THE    BABCOCK    &     WILCOX 
WATER-TUBE   BOILER. 


We  learn  quite  as  much  from  the  record  of 
failures  as  through  the  results  of  success.  When 
a  thing  has  been  once  fairly  tried  and  found  to 
be  impracticable,  or  imperfect,  the  knowledge  of 
that  trial  forms  a  beacon  light  to  warn  those  who 
come  after  not  to  run  upon  the  same  rock.  Still 
it  is  an  almost  everyday  occurrence  that  a  de- 
vice or  construction  which  has  been  tried  and 
found  wanting  if  not  worthless,  is  again  brought 
up  as  a  great  improvement  upon  other  things 
which  have  proved  by  their  survival  to  have  been 
the  ' '  fittest. ' '  This  is  particularly  the  case  when 
a  person  or  firm  have,  by  long  and  expensive 
experience,  succeeded  in  supplying  a  felt  want, 
and  developed  a  business  which  promises  to  pay 
them  in  the  end  for  their  trouble  and  outlay; 
immediately  a  class  of  persons,  who  desire 
to  reap  where  they  have  not  sown,  rush  into 
the  market  with 
something  similar, 
and,  generally,  with 
some  idea  which  the 
successful  party  had 
tried  and  discarded, 
claiming  it  as  an 
"  improvement," 
seek  to  entice  cus- 
tomers, who  in  the 
end  find  they  have 
spent  their  money 
for  that  which  sat- 
isfieth  not.  And 
not  infrequently 
steam  users,  having 
been  inadvertently 
induced  to  experiment  on  the  ill-digested  plans 
of  some  unfledged  inventor,  unjustly  condemn 
the  whole  class,  and  resolve  henceforth  to  stick 
to  the  things  their  fathers  approved. 

The  success  of  the  Babcock  &  Wilcox  boiler 
is  due  to  many  years  constant  adherence  to  one 
line  of  research,  experimenting  and  practical 
working.  In  that  time  they  have  tried  many 
plans  which  have  not  proved  to  be  practicable, 
and  were  in  fact,  in  whole  or  in  part,  failures. 
During  this  time  they  have  seen  moi^e  than  thirty 
water-tube  or  sectional  boilers  put  upon  the 
market,  by  other  parties,  some  of  which  attained 
to  some  distinction  and  sale,  but  all  of  which 
have  completely  disappeared,  leaving  scarce 
a  trace  behind,  save  in  the  memories  of  their 
victims.  The  following  list — not  complete — 
will  serve  to  bring  the  names  of  some  to  memo- 
ries  which    can    recall    twenty   years   or   less : 


Dimpfel,  Howard,  Cirifhth  &  Wundrum,  Dins- 
more,  Miller  "Fire-box,"  Miller  "American," 
Miller  ' '  Internal  Tube, ' '  Miller  ' '  Inclined  Tube," 
Phleger,  Weigand,  the  Lady  Verner,  the  Allen, 
the  Kelly,  the  Anderson,  the  Rogers  &  Black, 
the  Eclipse  or  Kilgore;  the  Moore,  the  Baker 
&  Smith,  the  Renshaw,  the  Shackleton,  the 
"  Duplex,"  the  Pond  &  Bradford,  the  Whitting- 
ham,  the  Bee,  the  Hazleton  or  "Common 
Sense,"  the  Reynolds,  the  Suplee  or  Luder,  the 
Babbitt,  the  Reed,  the  Smith,  the  Standard,  &c. 
It  is  with  the  object  of  protecting  our  custom- 
ers and  friends  from  disappointment  and  loss 
through  purchasing  such  discarded  ideas,  that 
we  publish  the  following  illustrations  of  experi- 
ments made  by  us  in  the  development  of  our 
present  boiler,  the  value  and  success  of  which  is 
evidenced  by  the  fact  that  the  largest  and  most 
discriminate  buyers  continue  to  purchase  them 
after  years  of  practical  experience  with  their 
workings. 


No.  I. — The  origi- 
nal Babcock&Wilcox 
boiler,  patented  in 
1 867 .  The  main  idea 
was  safety;  to  it  all 
other  elements  were 
sacrificed  wherever 
they  conflicted.  The 
boiler  consisted  of  a 
nest  of  horizontal 
tubes  serving  as 
steam  and  water  res- 
ervoir, placed  above 
and  connected  at 
each  end  by  bolted 
joints,  to  a  nest  of  inclined  heating  tubes  filled 
with  water.  Internal  tubes  were  placed  in  these 
latter  to  assist  circulation.  The  tubes  were 
placed  in  vertical  rows  above  each  other,  each 
vertical  row  and  its  connecting  end  forming  a 
single  casting.  Hand  holes  were  placed  at  the 
end  of  each  tube  for  cleaning. 

No.  2. — The  internal  circulation  tubes  were 
found  to  hinder,  rather  than  help,  circulation 
and  were  left  out. 

Nos.  I  and  2  were  found  to  be  faulty  in  both 
material  and  design,  cast  metal  proving  itself 
unfit  for  heating  surfaces  placed  directly  over 
the  fire,  cracking  as  soon  as  they  became  coated 
with  scale. 

No.  3. — Wrought-iron  tubes  were  substituted 
for  the  cast-iron  heating  tubes,  the  ends  being 
brightened  and  laid  in  the  mould,  the  headers 
cast  on. 


^ 


31 


-^ 


■*::' 


The  steam  and  water  capacity  was  in- 
sufficient to  secure  regularity  of  action, 
having  no  reserve  to  draw  upon  when 
irregularly  fed  or  fired.  The  attempt  to 
dry  the  wet  steam,  produced  by  super- 
heating in  the  nest  of  tubes  which 
formed  the  steam  space,  was  found  to 
be  impracticable  ;  the  steam  delivered 
was  either  wet,  dry,  or  superheated, 
according  to  the  demands  upon  the 
boiler.  Sediment  was  found  to  lodge 
in  the  lowest  point  of  the  boiler  at  the 
rear  end,  and  the  exposed  portion  of 
the  castings  cracked  oft"  when  subjected  to  the 
furnace  heat. 

No.  4. — A  plain  cylinder  carrying  the  water 
Hue  at  the   center,    leaving  the  upper  half  for 


steam 
tubes. 


of 


space,  was  substituted  for  the  nest 
The  sections  were  made  as  in  No.  3, 
and  a  mud-drum  added  to  the  rear  end  of  the 
sections  at  the  lowest  point  farthest  removed 
from  the  fire  ;  the  gases  passed  off  to  the  stack 
at  one  side  without  coming  in  contact  with  it. 
Dry  steam  was  secured  by  the  great  increase 
of  separating  surface  and  steam  space,  and  the 
added  water  capacity  furnished  a  storage  for 
heat  to  tide  over  the  irregularities  of  feeding 
and  firing.  By  the  addition  of  the 
drum  it  lost  a  little  in  safety,  but,  on 
the  other  hand,  it  became  a  serviceable 
and  practical  design,  retaining  all  the 
elements  of  safetj'  except  small  diame- 
ter of  steam  reservoir,  which  was  never 
large,  and  was  removed  from  the  direct 
action  of  the  fire,  but  difficulties  were 
encountered  in  securing  reliable  joints 
between  the  v/rought-iron  tubes  and 
the  cast-iron  headers. 

No.  5. — Wrought-iron  water  legs  were 
substituted  for  the  cast-iron  headers  ; 
the  tubes  were  expanded  into  the  in- 
side sheets,  and  a  large  cover  placed  opposite 
the  front  end  of  the  tubes  for  cleaning.     The 
staggered  position  of  tubes,  one  above  the  other. 


was  introduced  and  found  to  be  more  efficient 
and  economical  than  where  the  tubes  were 
placed  in  vertical  rows.  In  other  respects  it  was 
similar  to  No.  4,  but  it  had  further  lost  the 
important  element  of  safety,  the  sec- 
tional construction,  and  a  very  objec- 
tionable feature,  that  of  flat  stayed 
surfaces,  had  been  introduced.  The 
large  doors  for  access  to  the  tubes  were 
also  a  cause  of  weakness.  A  large 
plant  of  these  boilers  was  placed  in  the 
Calvert  Sugar  Refinery,  Baltimore,  and 
did  good  work,  but  they  were  never 
duplicated. 

No.  6. — A  modification  of  No.  5,  in 
which  longer  tubes  were  used,  with 
three  passages  of  the  gases  across  them, 
to  obtain  better  economy.  Also  some  of  the 
stayed  surfaces  were  omitted  and  hand  holes 
were  substituted  for  the  large  doors.  A  number 
of  this  type  were  built,  but  their  excessive  first 
cost,  lack  of  adjustability  of  the  structure  under 
varying  temperatures,  and  the  inconvenience 
of  transporting  the  last  two  styles  together  with 
the  difficulty  of  erecting  large  plants  without 
enormous  cost  for  brickwork,  as  well  as  the 
' '  commercial  engineering ' '  of  several  competing 


^^ 


No.  6. 

firms  then  in  the  market,  who  made  a  selling 
point  of  their  ability  to  add  power  to  any  given 
boiler  after  it  had  once  been  erected,  led  to  :  — 


T" 


32 


No.  7. — In  this,  separate  T  heads  were  screwed 
on  to  the  end  of  each  inclined  tube  ;  their  faces 
milled  off,  the  tubes  placed  on  top  of  each  other, 
metal  to  metal,  and  bolted  together  by  long  bolts 


No.  10. — A  nest  of  small  horizontal  drums, 
15  inches  in  diameter,  were  used  instead  of  the 
single   drums   of   larger   diameter ;    and   a   set 


No.  7. 

passed  through   each   vertical  section   of   tube 
heads,  and  the  connecting  boxes  on  the  heads  of 
the  drum.     A  large  number  of  these  boilers  were 
put  into  use,  some  of  which  are  still  at 
work  after  sixteen  to  twenty  years,  but 
most  of  them  have  been  altered  to  the 
later  type. 

Nos.  8  and  9  are  what  were  known 
as  the  Griffith  &  Wundrum  boilers, 
afterwards  merged  into  the  Babcock 
&  Wilcox.  In  these,  experiments  were 
made  on  four  passages  of  the  gases 
across  the  tubes,  and  the  downward 
circulation  of  the  water  at  the  rear  end 
of  the  boiler  was  carried  to  the  bottom 
row  of  tubes.  In  No.  9,  an  attempt 
was  made  to  reduce  the  amount  of  steam  and 
water  capacity,  increase  the  safety  and  reduce  the 
cost.     A  drum  at  right  angle  to  the  line  of  tubes 


No.  9. 

of  circulation  tubes  were  placed  at  an  inter- 
mediate angle,  between  the  main  bank  of 
heating  tubes   and  the  horizontal  tubes  which 


No.  10. 


formed  the  steam  reservoir,  to  return  the  water 
carried  up  by  the  circulation  to  the  rear  end 
of  the  heating  tubes,  allowing  the  steam  only 


No.  8. 

was  tried,  but  as  no  provision  was  made  for  se- 
curing dry  steam  the  results  were  not  satisfactory, 
and  the  next  move  in  the  direction  of  safety  was: 


No.  11. 


to  be  delivered  into  the  small  drums  above. 
The  result  was  no  improvement  in  action  over 
No.  9.      The  four  passages   of  the  gases  did 


33 


■^ 


I 


not  add  to  the  economy  in  either  No.  S,. 
9,  or  lo. 

No.  II. — A  trial  of  a  box  coil  system  in 
which  the  water  was  made  to  traverse 
several  times  through  the  furnace  before 
being  delivered  into  the  drum  above. 
The  tendenc}'  was,  as  in  all  similar  boilers, 
to  form  steam  in  the  middle  of  the  coil 
and  blow  the  water  out  from  each  end, 


No.  12. 

leaving  the  tubes  practically  dry  until  the  steam 
found  an  outlet  and  the  water  returned.  This 
boiler  not  only  had  a  defective  circulation  but  a 
decidedly  geyser-like  action,  and  produced  wet 
steam. 

All  the  above  types,   with  the  exception   of 
Nos.   5  and  6,   had  a   large  number  of  bolted 


No.  14. 


joints  between  their  seve/al  parts  and 
many  of  them  leaked  seriously,  from 
unequal  expansion,  as  soon  as 
the  heating  surfaces  became  scaled; 
enough  boilers  having  been  placed 
at  work  to  demonstrate  their  unreli- 
ability in  this  particular. 

No.  12. — An  attempt  to  avoid  this 
difficulty  and  increase  the  heating 
surface  in  a  given  space.  The  tubes 
were  expanded  into  both  sides  of 
wrought-iron  boxes,  openings  being 
made  in  them  for  the  admission  of 
water  and  the  exit  of  steam.  Fire- 
tubes  were  placed  inside  these  tubes 


No.  15. 

to  increase  the  surface.  These  were  abandoned 
because  they  quickly  stopped  up  with  scale,  and 
could  not  be  cleaned. 

No.  13. — Water  boxes  formed  of  cast-iron  of 
the  full  width  and  height  of  the  bank  of  tubes 
1  were  made  of  a  single  casting,  which  were  bolted 
to  the  steam  water-drum  above. 

No.  14. — A  wrought-iron  box  was  substituted 

In  this,  stays  were  necessary 

and  were  found,  as  is  always  the  case,  to  be  an 

element  to  be  avoided  wherever  possible.     It 


^^^^^^3  for  the  cast-iron 


34 


-►-^ 


was,  however,  an  improvement  on  No.  6.  A 
slanting  bridge  wall  underneath  the  drum  was 
introduced  to  throw  a  larger  portion  of  its  sur- 
face into  the  first  combustion  chambei"  above 
the  bank  of  tubes.  This  was  found  to  be  of  no 
special  benefit,  and  difficult  to  keep  in  good  order. 
No.  15. — Each  vertical  row  of  tubes  was 
expanded  at  each  end  into  a  continuous  header, 
cast  of  car  wheel  metal  ;  the  headers  having  a 
sinuous  form  so  that  they  would  lie  close  together 


In  No.  16  the  headers  were  made  in  the  form 
of  triangular  boxes,  having  three  tubes  in  each, 
The.se  were  alternately  reversed  and  connected 
together  by  short  pieces  of  tube  expanded  in 
place,  and  to  the  drum  by  tubes  bent  so  as  to 
come  normal  to  the  shell.  The  joints  between 
the  headers  introduced  an  element  of  weakness, 
and  connections  to  the  drum  were  insufficient  to 
give  the  adequate  circulation. 

No.    17. — Straight  horizontal   headers   were 


No.  16 


and  admit  of  a  staggered  position  of  the  tubes  in 
the  furnace.  This  form  of  header  has  been  found 
to  be  the  best  for  all  purposes,  and  has  not  since 
been  materially  changed.  The  drum  was  sup- 
ported by  girders  resting  on  the  brickwork. 
Bolted  joints  were  discarded,  with  the  exception 
of  those  connecting  the  headers  to  the  front  and 
rear  end  of  the  drum  and  the  bottom  of  the  rear 
header  to  the  mud-drum.  But  even  these  bolted 
joints  were  found  objectionable  and  were  super- 
seded in  subsequent  constructions  by  pieces  of 
tube  expanded  into  bored  holes. 


tried,  alternately  shifted  right  and  left,  to  give  a 
staggered  position  to  the  tubes.  These  headers 
were  connected  to  each  other  and  to  the  drum 
by  expanded  nipples.  This  was  open  to  about 
the  same  objection  as  No.  16. 

Nos.  18  and  19  were  designed  primarily  for 
fire  protection  purposes,  the  requirements  being 
a  small  compact  boiler,  and  the  ability  to  raise 
steam  quickly.  They  both  served  their  purpose 
admirably,  but,  as  in  No.  9,  the  only  provision 
made  for  securing  dry  steam  was  the  steam 
dome  shown  in  the  cuts.     This  dome  was  found 


►h- 


35 


inadequate  and  has  since  been  abandoned  in 
nearly  all  forms  of  boiler  construction.  No 
other  remedy  being  suggested  at  the  time,  they 
were  not  considered  as   desirable  for  general 


I  St.  Sinuous  headers  for  each  vertical  row  of 
tubes.  2d.  A  separate  and  independent  con- 
nection with  the  drum,  both  front  and  rear,  for 
each  such  vertical  row  of  tubes.     3d.  All  joints 


w^TEtl  Line, 


No.  18. 

use  as  the  later  construction  shown  in  Nos.  21 
and  22.  In  Europe,  however,  where  small  sizes 
were  more  in  demand,  No.  18  was  modified  and 
largely  used  with  excellent  results. 

No.  20.     The  development  of  the  B.  and  W. 


No.  20. 

Marine  boiler,  in  which  the  cross -drum  is 
used  exclusively,  and  the  experience  of  our 
Glasgow  works  with  No.  18  proved 
that  proper  attention  to  details  of  con- 
struction would  make  No.  18  a  most 
desirable  form  for  buildings  where 
head  room  was  limited,  and  with  this  in 
view  No.  20  was  designed,  with  the  result 
that  a  large  number  of  these  boilers 
have  been  put  in  use  under  widely 
varying  conditions  without  a  single 
adverse  report. 

These  experiments,  as  they  may  be 
called,  although  many  boilers  were  built 
of  some  of  the  styles  illustrated,  clearly 
demonstrated  that  the  best  construction 
and  efficiency  required  adherence  to  the 
following  elements  :  — 


No.  19. 

between  the  parts  of  the  boiler  proper  to  be 
made  without  bolts  or  screw-threads.  4th.  No 
surfaces  to  be  used  which  require  to  be  stayed. 
5th.  The  boiler  supported  independently  of  the 
brickwork,  so  as  to  be  free  to  expand  and  con- 
tract as  it  was  heated  and  cooled. 
6th.  The  drums  not  less  than  30 
inches  in  diameter,  except  for 
small  boilers.  7th.  Every  part 
accessible  for  cleaning  and  repair. 
Having  settled  upon  these 
points  : 

No.  21  was  designed,  having  all 
these  features,  together  with  other 
improvements  in  the  details  of 
construction.  The  general  form 
of  construction  of  No.  15  was 
adhered  to,  but  short  pieces  of 
boiler  tube  were  used  as  connec- 
tions between  the  sections  and 
drum,  and  mud-drum ;  their  ends  being  ex- 
panded into  adjacent   parts   with    a    Dudgeon 


^ 


No.  21. 


36 


■^ 


No.  21. 

expander.  This  boiler  was  also  suspended 
entirely  independent  of  the  brickwork  by  means 
of  columns  and  girders,  and  the 
mutually  deteriorating  strains  where 
one  was  supported  by  the  other  were 
avoided. 

Since  this  construction  was  adopted 
hundreds  of  thousands  of  horse- 
power of  this  style  have  been  built, 
giving  excellent  satisfaction.  It  is 
known  as  our"C.  I.  F."  (cast-iron 
front)  style,  a  fancy  cast-iron  front 
being  generally  used  therewith,  as 
shown  in  the  perspective  view.  Re- 
cent investigations  have  shown  that 
the  average  cost  of  up-keep  of  the 
boiler  proper  is  less  than  five  cents 
per  horse-power  per  annum. 

No.  22  is  known  as  our  "  W.  I.  F." 
style,  the  front  usually  supplied  with 
it  being  largely  made    of   wrought  -  iron.      In 
this  boiler,  flanged  and  "bumped"  drum  heads 


of  wrought-steel  are  used  ;  the  drum 
is  longer,  and  the  sections  are  con- 
nected to  cross-boxes  riveted  to  its 
bottom.  Where  height  is  to  be  saved, 
the  steam  is  taken  out  through  nozzles 
placed  on  the  drum  heads.  In  this 
style  also  the  drum  is  suspended  from 
columns  and  girders. 

No.    23.       The    "Vertical    Header 

Style"  has  the  same  general  features 

-S^       of  construction  with  the  exception  of 

~-S       having   the    tube -sheet    side   of    the 

header  ' '  stepped ' '  so  that  the  header 

may  be  placed  at  right  angles  to  the 

drum,    instead  of  having  it   inclined 

in  Nos.  21  and  22.     This  form  permits  of 

shorter  brick  setting,   thereby  reducing  the 


cost 

Nos. 


of  erection  and  the  floor  space  occupied. 
20,    22,    and   23   have  now  become  the 
standard    forms,    although   No.   21   is 
still  furnished  occasionally. 

The  last  step  in  the  development 
of  the  water  -  tube  boiler,  beyond 
which  it  seems  almost  impossible  for 
science  and  skill  to  go,  consists  in  mak- 
ing all  parts  of  the  boiler  of  wrought- 
steel,  including  the  sinuous  headers, 
the  cross-boxes,  and  the  nozzles  on  the 
drum.  This  was  demanded  to  answer 
the  laws  of  some  of  the  Continental 
Nations,  and  the  Babcock  &  Wilcox 
Co.  have,  at  the  present  time,  a  plant 
turning  out  forgings,  as  a  regular  bus- 
iness, which  have  been  pronounced  by 
the  London  Engineer  to  be  "a  perfect 
triumph  of  the  forgers'  art." 


4t 


37 


■^ 


CONSTRUCTION. 

This  boiler  is  composed  of  lap-welded  wrought 
iron  tubes,  placed  in  an  inclined  position  and 
connected  with  each  other,  and  with  a  horizontal 
steam  and  water  drum,  by  vertical  passages  at 
each  end,  while  a  mud-drum 
is  connected  to  the  rear  and 
lowest  point   in  the   boiler. 

The  end  con- 
nections are  in 
one  piece  for 
each  vertical 
row  of  tubes, 
and  are  of  such 
form  that  the 
tubes  are  ' '  stag- 
gered" (or  so 
placed  that  each 
row  comes  over 
the  spaces  in  the 
previous    row). 

The  holes  are  accurately  sized, 
made  tapering,  and  the  tubes 
fixed  therein  by  an  expander. 
The  sections  thus  formed  are 
connected  with  the  drum,  and 
with  the  mud-drum  also  by 
short  tubes  expanded  into  bored 
holes,  doing  away  with  all  bolts, 
and  leaving  a  clear  passage  way 
between  the  several  parts.  The 
openings  for  cleaning  opposite 
the  end  of  each  tube  are  closed 
by  hand-hole  plates,  the  joints 
of  which  are  made  in  the  most  thorough  manner, 
by  milling  the  surfaces  to  accurate  metallic  con- 
tact, and  are  held  in  place  by  wrought-iron  forged 
clamps  and  bolts.  They  are  tested  and  made 
tight  under  a  hydrostatic  pressure  of  300  pounds 
per  square  inch,  iron  to  iron,  atid  without  rubber 
packing,  or  other  perishable  substances. 

The  steam  and  water  drums  are  made  of  flange 
iron  or  steel,  of  extra  thickness,  and  double 
riveted.  They  can  be  made  for  any  desired 
pressure,  and  are  always  tested  at  50%  above 
the  pressure  for  which  they  are  constructed. 
The  mud-drums  are  of  cast-iron,  as  the  best 


material  to  withstand  corrosion,   and  are  pro- 
vided with  ample  means  for  cleaning. 


ERECTION. 

In  erecting  this  boiler,  it  is  sus- 
pended entirely  independent  of 
the    brickwork,    from   wrought 


END  VIEW  OF 
HEADER. 


PARTIAL  VERTICAL  SECTION. 

iron  girders  resting  on  iron  columns.  This 
avoids  any  straining  of  the  boiler  from  unequal 
expansion  between  it  and  its  enclosing  walls, 
and  permits  the  brickwork  to  be  repaired  or 
removed,  if  necessary,  without  in  any  way  dis- 


4t 


4-^ 


39 


^ 


•^-i 


turbing  the  boiler.     All  the  fixtures  are  extra 
heavy  and  of  neat  designs. 

OPERA  TION. 

The  fire  is  made  under  the  front  and  higher 
end  of  the  tubes,  and  the  products  of  the  com- 
bustion pass  up  between  the  tubes  into  a  com- 
bustion chamber  under  the  steam  and  water 
drum ;  from  thence  they  pass  down  between 
the  tubes,  then  once  more  up  through  the 
spaces  between  the  tubes,  and  off  to  the  chim- 
ney. The  water  inside  the  tubes,  as  it  is 
heated,  tends  to  rise  towards  the  higher  end, 
and  as  it  is  converted  into  steam — the  mingled 
column  of  steam  and  water  being  of  less  spe- 
cific gravity  than  the  solid  water  at  the  back 
end  of  the  boiler — rises  through  the  vertical 
passages  into  the  drum  above  the  tubes,  where 
the  steam  separates  from  the  water  and  the 
latter  flows  back  to  the  rear  and  down  again 
through  the  tubes  in  a  continuous  circulation. 
As  the  passages  are  all   large  and  free,   this 


posed  to  the  fire,  not  only  hinder  the  trans- 
mission of  heat  to  the  water,  but  admit  of 
overheating,  and  even  burning  the  side  next 
the  fire,  with  consequent  strains,  resulting  in 
loss  of  strength,  cracks,  and  tendency  to  rup- 


Forged  Steel  Drum  Nozzle. 


ture.  This  is  admittedly  the  direct  cause  of 
many  explosions.  Water-tubes,  however,  ad- 
mit of  thin  envelopes  for  the  water  next  the 
fire,  with  such  ready  transmission  of  heat  that 
even  the  fiercest  fire  cannot  overheat  or  injure 
the  surface,  as  long  as  it  is  covered  with  water 
upon  the  other  side. 

2 — Joints  Removed  from  the  Fire. 
Riveted  joints  with  their  consequent  double 
thickness  of  metal,  in  parts  exposed  to  the  fire. 


Forged  Steel   Header  Hand  Hole  Fittings. 


circulation  is  very  rapid,  sweeping  away  the 
steam  as  fast  as  formed,  and  supplying  its  place 
with  water ;  absorbing  the  heat  of  the  fire  to 
the  best  advantage ;  causing  a  thorough  com- 
mingling of  the  water  throughout  the  boiler 
and  a  consequent  equal  temperature,  and  pre- 
venting, to  a  great  degree,  the  formation  of 
deposits  or  incrustations  upon  the  heating 
surfaces,  sweeping  them  away 
and  depositing  them  in  the 
nmd-drum,  whence  they  are 
blown  out. 

The  steam  is  taken  out  at  the 
top  of  the  steam-drum  near  the 
back  end  of  the  boiler  after  it 
has  thoroughly  separated  from 
the  water,  and  to  insure  dry 
steam  a  perforated  dry-pipe  is  connected  to 
the  nozzle  inside  the  drum. 

ADVANTAGES. 

The  following  are  the  prominent  advantages 
which  this  boiler  presents  over  those  of  the 
ordinary  construction: — 

1  .  —  Thin  Heating  Surface  in  Furnace. 

The  thick  plates  necessarily  used  in  ordinary 
boilers,    in    the    furnace,    or    immediately    ex- 


Forged  Steel 
Manhole  Plate. 


give  rise  to  serious  difficulties.  Being  the 
weakest  parts  of  the  structure,  they  concen- 
trate upon  themselves  all  strains  of  unequal 
expansion,  giving  rise  to  freqtient  leaks,  and 
not  rarely  to  actual  rupture.  The  joints  be- 
tween tubes  and  tube  sheets  also  give  much 
trouble  when  exposed  to  the  direct  fire,  as  in 
locomotive  and  tubular  boilers.  These  diffi- 
culties are  wholly  overcome  by  the  use  of  lap- 
welded  water-tubes,  with  their  joints  removed 
from  the  fire. 

3. — Large  Draft  Area. 

This,  which  is  limited  in  fire-tubes  to  the 
actual  area  of  the  tubes,  in  this  boiler  is  the 
whole  chamber  within  which  the  tubes  are  en- 
closed, which,  with  down  draft,  gives  ample 
time  in  the  passage  of  the  heated  gases  to  the 
chimney  for  thorough  absorption  of  their  heat. 

4. — Complete  Combustion, 

The  perfection  of  combustion  depends 
upon  a  thorough  mixture  of  the  gases 
evolved  from  the  burning  of  fuel  with  a 
proper  quantity  of  atmospheric  air  ;  but 
this  perfect  mixture  rarely  occurs  in  or- 
dinary  furnaces,    as   is   proved   by    chemical 


41 


■^ 


analysis,  and  also  b}'  the  escapd  of  smoke,  upon 
the  introduction  of  any  smoke-producing  fuel. 
Even  when  smoke  is  notvisible  a  large  percentage 
of  the  combustible  gases  may  be  escaping  into 
the  chimney,  in  the  form  of  carbonic  oxide,  or 
half-burned  carbon.  Numerous  attempts  have 
been  made  to  cure  this  evil,  by  admitting  air  to 
the  furnace  or  flues,  to  "burn  the  smoke";  but 
though  this  may  allow  so  much  air  to  mingle 
with  the  smoke  as  to  render  it  invisible,  and  at 


furnace  are  broken  up  and  thoroughly  mingled  by 
passing  between  the  staggered  tubes,  and  have  an 
opportunity  to  complete  their  combustion  in 
the  triangular  chamber  between  the  tubes  and 
drum. 

That  this  does  really  take  place  is  proved  by 
an  analysis  by  Dr.  Behr  of  the  escaping  gases 
from  a  stack  of  these  boilers  at  Mattheissen  & 
Weicher's  sugar  refinery.  He  made  many  sepa- 
rate analyses  at  different  times,  and  in  no  case 


n    i\ 


standard  Front  of  Babcock  &  Wilcox  Boiler. 


the  same  time  ignite  some  of  the  lighter  gases,  it 
in  reality  does  little  to  promote  combustion,  and 
the  cooling  effect  of  the  air  more  than  over- 
balances all  the  advantages  resulting  from  the 
burning  gas.  The  analysis  of  gases  from  various 
furnaces  shows  almost  uniformly  an  excess  of 
free  oxygen,  proving  that  sufficient  air  is  ad- 
mitted to  the  furnace,  and  that  a  more  thorough 
and  perfect  mi:x:ing  is  needed.  Every  particle 
of  gas  evolved  from  the  fuel  should  have  its 
equivalent  of  oxygen,  and  must  find  it  while  hot 
enough  to  combine,  in  order  to  be  effective.  In 
this  boiler  the  currents  of  gases  after  leaving  the 


was  there  more  than  a  trace  of  carbonic  oxide, 
even  when  there  was  less  than  one  per  cent,  of 
uncombined  oxygen. 

5. — Thorough  Absorption  of  the  Heat. 
There  are  important  advantages  gained  in  this 
respect  in  consequence  of  the  course  of  the  gases 
being  more  nearly  at  right  angles  to  the  heating 
surface,  impinging  thereon  instead  of  gliding  by 
in  parallel  lines  as  in  fire-tube  boilers.  The  cur- 
rents passing  three  times  across  and  between  the 
staggered  tubes  are  brought  intimately  in  con- 
tact with  all  parts  of  the  heating  surface,  render- 


42 


■^ 


ing  it  much  more  efficient  than  the  same  area  in 
ordinary  tubular  boilers. 

The  experiments  of  Doctor  Alban  and  of  the 
U.  S.  Navy  have  proved  that  a  given  surface 
arranged  in  that  manner  is  thirty  per  cent,  more 
efficacious  than  when  in  the  form  of  fire  tubes  as 
usually  employed. 

6. — Efficient  Circulation  of  Water. 
As  all  the  water  in  the  boiler  tends  to  circulate 
in  one  direction,  there  are  no  interfering  currents, 
the  steam  is  carried  quickly  to  the  surface,  all 
parts  of  the  boiler  are  kept  at  a  nearly  equal  tem- 
perature, preventing  unequal  strains,  and  by  the 
rapid  sweeping  current  the  tendency  to  deposit 
sediment  on  the  heating  surface  is  materially 
lessened. 

7. — Quick  Steaming. 

The  water  being  divided  in  many  small  streams, 
in  thin  envelopes,  passing  through  the  hottest 
part  of  the  furnace,  steam  may  be  rapidly  raised 
in  starting,  and  sudden  demands  upon  the  boiler 
may  be  met  by  a  quickly  increased  efficiency. 


and  the  ample  passages  for  circulation,  secure  a 
steadiness  of  water  level  not  surpassed  by  any 
boiler.  This  is  a  most  important  point  in  boiler 
construction  and  should  always  be  considered 
when  comparing  the  horizontal  and  vertical  types 
of  water-tube  boilers.  Take,  for  instance,  a 
Babcock  and  Wilcox  boiler  of  250  H.P.  and 
a  well  known  vertical  water-tube  boiler.  The 
former  lowers  its  water  line  at  the  rate  of  one 
inch  in  5.87  minutes,  and  the  latter  at  the  rate 
of  one  inch  in  1.15  minutes.  Or  if  we  suppose 
the  feed  pumps  to  break  down  when  the  boilers 
are  running  at  their  rated  capacity  and  the 
water  line  is  at  the  normal  height,  it  will  be  one 
hour  and  23  minutes  before  the  water  is  all  out 
of  the  drum  of  the  B.  &  W.  boiler,  while  with 
the  vertical  boiler  the  crown  sheet  will  be  bare 
in  20.9  minutes. 

10. — Freedom  of  Expansion. 
The  arrangement  of  the  parts,  forming  a  flex- 
ible structure,    allows  any  member  to  expand 
without  straining  any  other,  the  expanded  con- 


Forged  Steel  Cross  Box. 


8. — Dryness  of  Steam. 
The  large  disengaging  surface  of  the  water  in 
the  drum,  together  with  the  fact  that  the  steam  is 
delivered  at  one  end  and  taken  out  at  the  other, 
secures  a  thorough  separation  of  the  steam  from 
the  water,  even  when  the  boiler  is  forced  to  its 
utmost.  Most  tubular,  locomotive,  and  sectional 
boilers  make  wet  steam,  "priming"  or  "foam- 
ing," as  it  is  called,  and  in  many  "  super-heating 
surface"  is  provided  to  "dry  the  steam";  but 
such  surface  is  always  a  source  of  trouble,  and  is 
incapable  of  being  graduated  to  the  varying  re- 
quirements of  the  steam.  No  part  of  a  boiler  not 
exposed  to  water  on  the  one  side  should  be  sub- 
jected to  the  heat  of  the  fire  upon  the  other,  as 
the  unavoidable  unequal  expansion  necessarily 
weakens  the  metal,  and  is  a  serious  source  of 
danger.  Hence  a  boiler  which  makes  dry  steam 
is  to  be  preferred  to  one  that  dries  steam  which 
has  been  made  wet. 

9. — Steadiness  of  Water  Level. 
The  large  area  of  surface  at  the  water  line. 


nections  being  also  amply  elastic  to  meet  all 
necessities  of  this  kind.  This  is  of  great  im- 
portance because  the  weakening  effect  of  these 
strains  of  unequal  expansion,  between  rigidly 
connected  parts,  is  a  prolific  cause  of  explosions 
in  ordinary  boilers.  The  rapid  circulation  of 
the  water,  however,  in  this  boiler,  by  keeping 
all  parts  at  the  same  temperature,  prevents  to  a 
large  extent  unequal  expansion. 

//. — Safety  from  Explosions. 
The  freedom  from  unequal  expansion  avoids 
the  most  frequent  cause  of  explosions,  while  the 
division  of  the  water  into  small  masses  prevents 
serious  destructive  effects  in  case  of  accidental 
rupture.  The  comparatively  small  diameter  of 
the  parts  secures,  even  with  thinness  of  surface, 
great  excess  of  strength  over  any  pressure  which 
it  is  desirable  to  use.  So  powerful  is  the  circula- 
tion of  the  water,  that  no  part  will  be  uncovered 
to  the  fire  until  the  quantity  of  water  in  the  boilet 
is  so  far  reduced  that  if  overheating  should  occur 
no  explosion  could  result. 


>"^ 


43 


4--^ 


12. — Capacity. 
This  is  a  point  of  the  greatest  importance,  and 
upon  it  depends,  in  a  large  measure,  tlie  satisfac- 
tory performance  of  any  boiler  in  several  particu- 
lars. Unless  sufficient  steam  and  water  capacity 
is  provided  there  will  not  be  regularity  of  action; 
the  steam  pressure  will  suddenly  rise  and  as  sud- 
denly fall,  and  the  water  level  will  be  subject  to 


room  is  therefore  generally  much  overrated,  but 
if  it  be  too  small  the  steam  in  passing  off  will 
sweep  the  water  with  it  in  the  form  of  spray. 
Too  much  water  space  makes  slow  steaming 
and  waste  of  fuel  in  starting.  Too  much  steam 
space  adds  to  the  radiating  surface  and  increases 
the  losses  from  that  cause.  The  proportions  of 
this  boiler  have  been  adopted  after  numerous 


Babcock  &  Wilcox  Boilers,  164  H.P.  Erected  1884,  for  Greenfield  &  Co.,  Confectioners,  Brooklyn,  N.Y. 
164  H.P.  additional  erected  in  1890. 


frequent  and  rapid  changes;  and  if  the  steam  is 
drawn  suddenly  from  the  boiler,  or  the  boiler 
crowded,  wet  steam  will  result. 

Water  capacity  is  of  more  importance  than 
steam  space,  owing  to  the  small  relative  weight 
of  the  steam.  Twenty-three  cubic  feet  of  steam, 
or  one  foot  of  water  space,  are  required  to  supply 
one  horse-power  for  one  minute,  the  pressure 
meantime  falling  from  8o  pounds  to  70  pounds 
per  square  inch.      The  value  of  large  steam 


experiments  with  boilers  of  varying  capacity; 
and  experience  has  established  that  this  boiler 
can  be  driven  to  the  utmost,  carrying  a  steady 
water  level,  and  steam  pressure,  and  always 
furnishing  dry  steam. 

The  cubical  capacity  of  this  boiler,  per  horse- 
power, is  equal  to  that  of  the  best  practice  in 
tubular  boilers  of  the  ordinary^  construction.  The 
fire  surface  being  of  the  most  effective  character, 
these  boilers  will,  with  good  fuel  and  a  reason- 


dt 


45 


■♦-"< 


ablj'  economical  engine,  greatly  exceed  thpir 
rated  power,  though  it  is  seldom  economy  to 
work  a  boiler  above  its  nominal  power.  The 
space  occupied  by  this  boiler  and  setting  is  equal 
to  about  two-thirds  that  of  the  same  power  in 
fire  tubular  boilers. 

13. — Accessibility  for  Cleaning. 
This  is  of  the  greatest  importance  and  is 
secured  to  the  fullest  extent.  Hand-holes,  with 
metal  joints,  opposite  each  end  of  each  tube, 
permit  access  thereto  for  cleaning,  and  a  man- 
hole in  the  steam  and  water  drum,  and  hand- 
holes  in  mud-drum,  are  provided  for  the  same 
purpose.  All  portions  of  both  the  exterior  and 
interior  surface  are  fully  accessible  for  cleaning. 
The  occasional  use  of  steam  through  a  blowing 
pipe  attached  to  a  rubber  hose  operated  through 
doors  in  the  side  walls,  will  keep  the  tubes  free 


tion  which  so  rapidly  destroys  the  ends  of  fire 
tubes,  or  to  the  blow-pipe  action  of  the  flame 
upon  the  crown  sheet,  bridge  walls,  and  tube 
sheets,  which  are  so  destructive  frequently  to  or- 
dinary-, particularly  locomotive,  boilers.  Neither 
is  there  any  portion  of  the  surface  above  the 
water  level  exposed  to  the  fire.  For  these  reasons 
these  boilers  are  durable,  and  less  liable  to 
repairs,  than  other  boilers  under  the  same  cir- 
cumstances, and  having  the  same  care. 

16. — Ease  of  Transportation. 
Being  made  in  sections,  which  are  readily  put 
together  with  a  simple  expanding  tool,  these 
boilers  may  be  easily  and  cheaply  transported 
where  it  would  be  impossible  to  place  a  boiler  of 
ordinary  construction.  They  can  be  made  in 
parts  small  enough  for  mule  transportation,  if 
required. 


Forged  Steel  Drum  Head. 


WATER-TUBE. 


FIRE-TUBE. 


from  soot  and  in  condition  to  receive  the  heat  to 
the  best  advantage. 

14. — Least  Loss  of  Effect  from  Dust. 
The  ordinary  fire-tube, 
or  flue,  receiving  the  dust 
from  the  fire  on  the  in- 
terior is  quickly  covered 
from  one-third  to  one- 
half  its   surface,  and  in 
time  is  completely  filled.     The  water-tube,  how- 
ever, will  retain  but  a  limited  quantity  on  its 
upper  side,  after  which  it  becomes  in  a  measure 
self-cleaning. 

15. — Durability. 

Besides  the  important  increase  of  durability 

due  to  the  absence  of  deteriorating  strains,  and 

of  thick  plates  and  joints  in  the  fire,  there  is  no 

portion  of  the  boiler  exposed  to  the  abrasive  ac- 


17. ^Repairs. 

As  now  constructed  these  boilers  seldom  re- 
quire repairs,  but  if,  from  any  cause,  such  should 
be  necessary,  any  good  mechanic  can  make  them 
with  the  tools  usually  found  in  boiler  shops. 
Should  a  tube  require  to  be  renewed  it  can  be 
removed,  and  a  new  one  substituted  the  same 
as  in  a  tubular  boiler. 

18. — Practical  Experience. 

The  above  advantages  would  be  wonhy  of 
attention  if  they  were  only  theoretical,  but  they 
have  been,  in  fact,  demonstrated  by  the  experi- 
ence of  twenty  years,  under  a  great  variety  of 
circumstances  and  of  treatment.  Of  the  total 
number  sold,  less  than  two  per  cent,  have,  so 
far  as  we  are  aware,  been  thrown  out  of  use; 
while  a  large  number  of  customers  have  repeated 
their  orders, — some  a  score  of  times, — as  will  be 
seen  by  the  list  of  references  hereto  appended. 


^ 


^ 


@%%^7y^ 


ULES  Xnd  PRAeiieAU  DATAt^ 


ECONOMY  IN  STEAM. 
Efficiency  of  the  Boiler. 
One  pound  of  pure  carbon  when  burned  yields 
14,500  heat  units,  each  of  which  is  equal  to  778 
foot  pounds  of  energy.  If  all  its  heat  was  utilized 
in  power,  it  would  therefore  exert  5,697  horse- 
power for  one  hour,  instead  of  from  ^  to  X.  as 
in  the  best  ordinary  practice.     The  14,500  heat 


by  no  less  than  twenty  different  engineers,  and, 
with  only  two  exceptions,  on  boilers  in  daily 
use  for  manufacturing  purposes,  in  England, 
Scotland,  and  from  Massachusetts  to  California 
in  the  United  States,  with  various  kinds  and 
grades  of  coals,  and  at  various  rates  of  com- 
bustion, covering  an  aggregate  of  nearly  three 
months'  regular  working,  and  evaporating  over 


Babcock  &  Wilcox  Boiler  at  Chavanne  Brun  et  Cie.,  diamond,  France. 

"  W.  I.  F."  style,  with  Wrought  Headers. 


248  H.P. 


units  would,  if  all  utilized  in  a  boiler,  evaporate  15 
pounds  of  water  from  212°  at  atmospheric  pres- 
sure. A  boiler  which  evaporates  y}4  pounds  of 
water  for  each  pound  of  combustible  utilizes  but 
50  per  cent,  of  the  total  heat,  and  this  is  about 
the  average  result  of  shell  boilers  now  in  use. 

The  Babcock  &  Wilcox  boilers,  in  //z/r/j/  ^es^s 
extending  over  the  last  twelve  years,  under  a 
great  variety  of  conditions  and  circumstances. 


three  thousand  tons  of  water,  gave  an  average 
evaporation  of  11. 42 17  pounds  water  per  pound 
of  combustible.  This  is  withmy'ou7^ per  cent,  of 
Rankine's  standard,  and  within  seven  and  one- 
half  per  cent,  of  the  highest  theoretical  efficiency, 
under  the  conditions  in  which  they  were  made. 
It  is  not  probable  that  any  kind  of  boiler,  fairly 
tested,  will  ever  beat  such  a  record.  As  about 
15  per  cent,  is  lost  in  the  chimney  gases,  and  in 


47 


■* 


*? 


radiation,  it  is  evident  that  all  claims  to  over 
12;^  pounds  evaporation  should  be  looked  iipon 
as  unreliable. 

A  steam  generator  is  composed  of  two  dis- 
tinct parts,  each  with  its  independent  function. 
The  furnace,  is  for  the  proper  combustion  of  the 
fuel,  and  its  duty  is  performed  to  perfection 
when  the   arreatest  amount  of  heat  is  obtained 


As  a  boiler  is  for  making  steam,  it  can  only 
utilize  for  that  purpose  heat  of  a  greater  intensity 
or  higher  temperature  than  the  steam  itself,  there- 
fore the  gases  of  combustion  cannot  be  reduced 
below  that  temperature,  and  the  heat  thereby 
represented  is  lost.  The  amount  of  this  loss  will 
depend  upon  the  amount  of  air  admitted  to  the 
furnace,  and  the  increase  of  temperature  at  which 


FRONT    VIEW. 

Babcock  &  Wilcox  Boiler  at  U.  S.  Centennial  Exhibition,  1876,    150  H.P. 


from  the  given  weight  of  combustible.  The 
boiler  proper  is  for  the  transfer  of  the  heat  thus 
generated  into  useful  effect  by  evaporating  water 
into  steam,  and  its  function  is  fulfilled  com- 
pletely when  the  greatest  possible  quantity  of 
heat  is  thus  utilized.  To  a  lack  of  appreciation 
of  this  fact,  and  of  a  knowledge  of  the  principles 
involved,  is  chargeable  much  waste  of  money 
and  disappointment,  both  to  inventors  and 
steam  users. 


it  escapes.  The  more  air  admitted  the  greater 
the  loss;  hence  the  fallacy  of  all  those  schemes 
which  admit  air  above  the  fire. 

' '  The  maximum  conductivity  or  flow  of  heat 
is  secured  by  so  designing  the  boiler  as  to  secure 
rapid,  steady,  and  complete  circulation  of  the 
water  within  it  .  .  .  and  securing  opposite  di- 
rections of  fiow  for  the  gases  on  the  one  side  and 
the  water  on  the  other." — Prof.  R.  H.  Thurston. 

The  accumulation  of  scale  on  the  interior,  and 


48 


of  soot  on  the  exterior,  will  seriously  affect  the 
efificiency  and  economy  of  the  boiler.  The 
amount  of  loss  clue  to  these  causes  has  been 
variously  estimated  and  the  best  authorities  seem 
to  hold  that  only  one-eighth  of  an  inch  deposit 
of  soot  renders  the  heating  surface  practically 
useless,  and  only  one-sixteenth  of  an  inch  of 
scale  or  sediment  will  cause  a  loss  of  13  per 
cent,  in  fuel,  but  while  these  figures  may  be 
wide  of  the  truth  yet  the  loss  is  undoubtedly 
very  large.  The  loss  due  to  incrustation  of  scale 
will  vary  with  the  chemical  composition  and 
porosity  of  the  deposit.  A  boiler  must,  there- 
fore, be  kept  clean,  outside  and  in,  to  secure  a 
high  efficiency. 

It  is  never  economy  to  force  a  boiler,  and  the 
best  results  are  always  attained  with  ample  boiler 
power.  It  is  also  necessary  to  keep  the  boiler, 
together  with  its  brickwork,  in  good  order,  and 
to  have  careful  firing  where  economy  is  desired. 

The  result  of  a  bad  setting  for  a  boiler  has 
been  known  to  be  a  loss  of  21  per  cent,  in 
economy. 

Efficiency  of  t/ie  Furnace. 

Combustion  may  be  defined  as  "  the  union  of 
two  dissimilar  substances,  evolving  light  and 
heat."  In  ordinary  practice,  one  of  these  is 
always  the  oxygen  in  the  atmosphere,  and  the 
other  is  the  fuel  employed.  Every  pound  of 
fuel  requires  a  given  quantity  of  oxygen  for  its 
complete  combustion,  and  thus  a  given  quantity 
of  air.  This  varies  with  different  fuels,  but  in 
every  case  less  air  prevents  complete  combus- 
tion, and  an  excess  of  air  causes  waste  of  heat 
to  the  amount  required  to  heat  it  to  the  tem- 
perature of  the  escaping  gas. 

With  chimney  draft,  the  experiments  of  the 
U.  S.  Navy  show  that  ordinary  furnaces  require 
about  twice  the  theoretical  amount  of  air  to 
secure  perfect  combusiion. 

Prof.  Schwackhoffer,  of  Vienna,  found  in  the 
boilers  used  in  Europe  an  average  excess  of  70 
per  cent,  of  the  total  amount  passing  through 
the  fire — or  that  over  three  times  the  theoret- 
ical amount  was  used. 

A  series  of  analyses  by  Dr.  Behr  of  the  escap- 
ing gases  from  a  Babcock  &  Wilcox  boiler,  with 
chimney  draft,  showed  an  average  excess  of  air 
equal  to  48  per  cent,  of  the  whole  quantity. 

A  series  of  12  tests  made  by  same  with  artifi- 
cial blast  gave  an  average  excess  of  only  22  per 
cent,  of  the  whole  quantity,  and  in  a  few  cases 
none  at  all,  with  only  traces  of  carbonic  oxide, 
showing  perfect  combustion. 

In  a  summary  of  experiments  made  in  England, 
published  in  Bourne's  large  work,  "Steam, 
Air,  and  Gas  Engines,"  it  is  stated  :  — 


"A  moderately  thick  and  hot  fire  with  rapid 
draft  uniformly  gave  the  best  results." 

"Combustion  of  black  smoke  by  additional 
air  was  a  loss." 

"In  all  experiments  the  highest  result  was 
always  obtained  when  all  the  air  was  introduced 
through  the  fire  bars." 

"Difference  in  mode  of  firing  only  may  pro- 
duce a  difference  of  13  per  cent."  (in  economy). 

Different  fuels  require  different  furnaces,  and 
no  one  furnace  or  grate-bar  is  ecjually  good  for 
all  fuels.  The  Babcock  &  Wilcox  Co.  provide 
with  their  boilers,  a  special  furnace,  adapted  to 
the  particular  kind  of  fuel  to  be  used. 

Efficiency  of  the  Engine. 

The  efficiency  of  the  steam  engine  is  often 
based  on  the  amount  of  fuel  burned  per  indi- 
cated horse-power  per  hour;  but  it  is  more 
properly  based  on  the  steam  consumption.  The 
highest  class  of  steam  engines  running  con- 
densing will  use  under  test  conditions  from 
twelve  to  twelve  and  one-half  pounds  of  water 
in  the  form  of  steam  per  I.  H.  P.  per  hour, 
while  the  ordinary  automatic  cut-off  engine 
with  single  expansion,  non-condensing,  uses 
from  28  to  35  pounds.  The  fuel  used  per  horse- 
power hour  therefore  depends  on  the  quality  of 
coal  and  the  efficiency  of  the  boiler  and  furnace 
as  well  as  upon  the  efficiency  of  the  engine. 

A  good  boiler  properly  set  and  fired  will  show 
a  much  higher  percentage  of  efficiency  than  the 
engine.  When  operated  with  high-grade  fuel  and 
under  the  best  conditions  a  boiler  may  deliver  to 
the  engine  as  much  as  75  %  of  the  theoretical  heat 
of  the  coal,  and  if  the  coal  contain  14,500  British 
thermal  units  per  pound  this  is  equivalent  to 
9.78  pounds  of  water  evaporated  from  a  feed 
temperature  of  120°  Fahr.  to  steam  at  200 
pounds  gauge  pressure.  If  the  engine  use  12 
pounds  of  steam  per  horse-power  hour  this 
means  a  coal  consumption  of  1.23  pounds  per 
I.  H.  P.  per  hour;  or  if  the  engine  use  30  pounds 
of  steam,  a  coal  consumption  of  3.07  pounds. 
These  figures  if  transposed  for  efificiency  would 
be  about  as  follows:  one  pound  of  coal  having 
14,500  B.T.U.  is  equivalent  to  11,281,000  foot 
pounds,  which  on  a  supposition  of  75%  effi- 
ciency in  the  boiler,  is  equal  to  8,460,750  foot 
pounds,  which  if  all  utilized  by  the  engine  would 
produce  4.29  H.P.  for  one  hour,  or  at  the  rate 
of  .233  pounds  of  coal  per  H.  P.  per  hour  instead 
of  the  amounts  above  stated.  On  this  basis  the 
highest  class  engine  has  an  efficiency  of  scarcely 
19%,  and  the .  other  of  a  Httle  more  than  7)4%, 
and  the  efificiency  of  engine  and  boiler  combined 
is  but  14^%  and  5.7%  respectively. 


49 


-^^ 


It  is  economy,  therefore,  in  most  cases,  to  use 
a  high-class  engine.  There  are  instances,  how- 
ever, where  the  engine  is  used  for  so  short  a 
time  in  each  year,  that  the  saving  may  not  be 
sufficient  to  pay  the  interest  on  the  additional 
cost,  and  a  cheaper  engine,  even  if  comparatively 
wasteful,  may  be  better  economy. 

Compound  engines,  when  high  pressures  can 
be  obtained,  have  an  advantage  in  economy  over 
single  cylinders,  and  ' '  triple ' '  and  ' '  quadruple' ' 
expansion  engines  under  some  conditions  show 
a  saving  over  simple  "compound."  But  they 
require  a  pressure  of  from  150  to  200  pounds, 
and  a  comparatively  steady  load,  to  develop  their 
advantages  to  a  great  degree.  Such  pressures  can 
be  safely  carried  on  Babcock  &  Wilcox  boilers. 

A  large  boiler  is  generally  an  advantage,  but 
it  is  not  economy  to  use  a  large  engine  to  develop 
a  small  power.  Sufficient  steam  to  fill  the  cylin- 
der at  the  terminal  pressure — each  stroke — has 
to  be  furnished  whether  the  engine  is  doing  more 
or  less  work,  and  this  frequently  amounts  to  far 
more  than  the  steam  used  to  do  the  work.  Thus, 
a  24  X  48  engine,  making  60  revolutions  per 
minute,  without  ' '  cut-off, ' '  uses  30  horse-power 
of  steam  in  displacing  the  atmosphere,  without 
exerting  any  available  power.  For  the  same 
reason  back  pressure  greatly  increases  the  cost 
of  the  power. 


Efficiency  of  Pumping  Engines. 

The  duty  of  the  different  types  of  steam  actu- 
ated pumps  and  pumping  engines  is  the  meas- 
ure of  their  efficiency  expressed  in  work  done 
per  unit  of  steam,  fuel,  or  heat  consumed  in  their 
operation. 

On  the  basis  of  the  unit  recommended  by  the 
American  Society  of  Mechanical  Engineers,  it  is 
the  number  of  foot  pounds  of  work  done,  as 
represented  by  the  weight  in  pounds  of  liquid 
pumped  multiplied  by  the  head  in  feet  against 
which  it  is  pumped,  for  each  i  ,000,000  British  ther- 
mal units  furnished  by  the  boiler  and  indicated 
by  the  weight  and  temperature  of  the  feed  water 
and  the  pressure  and  quality  of  the  steam  used. 

Or,  assuming  the  use  of  a  good  grade  of  coal 
and  an  efficient  boiler  and  furnace,  the  duty  of  a 
pumping  engine  is  the  amount  of  work  done  as 
measured  at  the  pump  plungers  for  each  100 
pounds  of  coal  consumed  on  the  grates,  or  for 
each  1035.5  pounds  of  steam  consumed, measured 
from  and  at  2 1 2  °  Fahr.  The  evaporation  of  1035 . 5 
pounds  of  water,  from  and  at  212°  Fahr. ,  requires 
the  transfer  of  1,000,000  British  thermal  units. 

The  boiler  horse-power  and  consequent  fuel 
consumption  required  for  a  given  pumping  serv- 
ice performed  varies  greatly  with  the  type  of 
steam  end  used  to  actuate  the  pumps,  as  shown 
by  the  following  table: — 


RELATIVE  EFFICIENCY  OF  DIFFERENT  TYPES  OF  PUMPING  ENGINES. 


Duty. 

Million  foot  pounds  work  done 

Pounds  of  Steam. 

Type. 

per  1000  pounds  steam  consumed, 

Per  pump  horse  power  per  hour. 

with 

varying  conditions  of  service. 

Condensijig-. 

Direct  acting  and  crank  and  flv-wheel,     Triple  expansion,  . 

125  to 

140 

16  to     13.5     . 

Direct  acting  and  crank  and  tiy-wheel,     Compound,  .     .     . 

100  to 

120 

20  to     i6- 

Direct  acting  low  duty, Triple  expansion,  . 

75  to 

90 

26  to     20 

Direct  acting  low  duty, Compound,   .     .     . 

40  to 

60 

50  to     33 

Noil-  Condensing. 

Direct  acting  low  duty, Triple  expansion,  . 

50  to 

70 

40  to    28 

Direct  acting  low  duty, Compound,   .     . 

30  to 

40 

66  to     50 

Direct  acting  small  sizes, Non-Compound,    . 

8  to 

20 

250  to  100 

Vacuum  pumps,  direct  acting,  independent 

8  to 

20 

250  to  100 

Vacuum  pumps,  fly  wheel,  independent, 

45  to 

80 

45  to     25 

2  to 

5 

FUEL. 

The  value  of  any  fuel  is  measured  by  the 
number  of  heat  units  which  its  combustion  will 
generate,  a  unit  of  heat  being  the  amount  re- 
quired to  heat  one  pound  of  water  one  degree 
Fahrenheit.  ' '  Combustible  ' '  is  that  portion 
which  will  burn ;  the  ash  or  residue  varying  from 
2  to  36  per  cent,  in  different  fuels. 

All  of  the  fuels  used  for  generating  steam 
depend  for  their  heating  value  upon  the  amount 
they  contain  of  the  two  chemical  elements, 
carbon  and  hydrogen.  Solid  fuels,  such  as  coal 
and  wood,  contain,  in  addition  to  these  useful 
elements,  other  substances  which  have  no  heat- 


ing value,  such  as  ash,  water,  and  oxygen,  the 
oxygen  being  in  chemical  combination  with  the 
hydrogen  and  carbon.  Most  coals  contain  also 
small  percentages  of  sulphur  (usually  in  the 
form  of  iron  pyrites)  and  of  nitrogen,  which  are 
of  no  value  as  fuel.  Liquid  fuels,  such  as 
petroleum  and  its  products,  are  nearly  pure 
compounds  of  carbon  and  hydrogen,  and  gas- 
eous fuels  contain  carbonic  oxide,  hydro-carbon 
gases,  and  hydrogen  as  their  heat-giving  sub- 
stances, with  other  constituents  which  are  of  no 
value  and  which  vary  greatly  in  amount  in  dif- 
ferent gases,  as  carbonic  acid,  nitrogen,  and 
occasionally  oxygen. 


•it 


50 


■n^ 


TABLE  OF  COMBUSTIBLES. 


Kind  of 
Combustible. 


Hydrogen, 

Petroleum, 

(  Charcoal, 
Carbon    I  Coke, 

'  Anthracite  Coal, 

Coal — Cumberland, 

Coal — Cokmg  Bituminous,      .     .     . 

Coal — Cannel,        

Coal — Lignite,        

Peat — Kiln  dried,       

Peat — Air  dried,  25  per  cent,  water. 

Wood — Kiln  dried, 

Wood — Air  dried,  20  per  cent,  water. 


Air  Re- 
quired. 


In 

Pounds, 

per 
pound  of 

Com- 
bustible 


36.00 
15-43 


12.06 
11-73 
11.80 
9-30 
7-68 
5.76 
6.00 
4.80 


Temperature  of  Combustion. 


With 
Theo- 
retical 
Supply 
of  Air. 


5750 
5050 

4580 

4900 
5140 
4850 
4600 
4470 
4000 
4080 
3700 


With  I J^ 
Times 
the  The- 
oretical 
Supply 
of  Air. 


3860 
35'5 

3215 

3360 
3520 
3330 
3210 
3140 
2820 
2910 
2607 


With 
Twice 
the  The- 
oretical 
Supply 
of  Air. 


2860 
2710 


2550 
2680 
2540 
2490 
2420 
2240 
2260 


With 
Three 
Times 
the  The 
oretical 
Supply 
of  Air. 


1940 
1850 

1650 

1730 
i8io 
1720 
1670 
1660 
1550 
1530 
1490 


Theoretical  Value. 


In  Pounds 
of  Water 
raised  1° 

per  pound 
of  Com- 
bustible. 


62032 
21000 

14500 

15370 
15837 
15080 

"745 
9660 
7000 
7245 
5600 


In  Pounds 
of  Water 
evaporated 
from  and  at 
212°,  with 
I  lb.  Com- 
bustible. 


04.20 
21.74 

15.00 

15.90 
16.00 
15.60 
12. 15 
10.00 
7-25 
7.50 
5.80 


Highest  Attainable 
Value  under  Boiler. 


With 

Chimney 

Draft. 


13-30 

14.28 

14-45 ■ 
14.01 
10.78 
8.92 
6.41 
6.64 
4.08 


With  Blast, 
Theoretical 

Supply  of 
Air  at  60°, 

Gas  320°. 


14.14 

15.06 
15.19 
14.76 
11.46 
9.42 
6.78 
7.02 
4-39 


TABLE  SHOWING  APPROXIMATE  CHEMICAL  COMPOSITION  OF  SEVERAL  TYPICAL  KINDS   OF  SOLID   FUELS. 


Wood,  perfectly  dry, 

Wood,  ordinary, 

Peat, 

Charcoal, 

Straw, 

Coal,  Anthracite, 

Coal,  Semi- Bituminous 

Coal,  Bituminous,  Pittsburg,  .  .  . 
Coal,  Bituminous, HockingValley.O., 
Coal,  Bituminous,  Illinois,  .... 
Brown  Coal,  Pacific  coast,  .... 
Lignite,  Pacific  coast, 


Carbon. 


40.6 

84 

36 

86 

84 

75 

67 

56 

50 

55 


Hydrogen. 


Oxygen. 


Nitrogen. 


i.o 

0.8 


Sulphur. 


0-5 
0.6 
1.6 
1-5 
3-0 


Ash. 


The  above  tables  show  approximately  the 
composition  and  heating  value  of  several  typical 
kinds  of  fuel.  It  is  not  possible  in  tables  of  this 
character  to  give  figures  that  are  accurate,  for 
the  reason  that  the  composition  of  the  different 
items  is  exceedingly  variable.  The  tables  are 
useful,  therefore,  only  when  fairly  approximate 
figures  are  desired. 

The  actual  heating  value  of  a  coal,  as  deter- 
mined by  test  with  an  instrument  known  as 
a  "bomb  calorimeter,"  agrees  very  closely 
with  that  calculated  from  the  analysis,  usually 
within  2  per  cent,  when  both  the  analysis  and 
the  calorimeter  test  are  made  by  a  skilled 
chemist. 

The  analyses  given  in  the  above  table  are 
called  "ultimate  analyses,"  since  the  constit- 
uents of  the  fuel,  except  the  moisture  and  ash, 
are  reduced  to  the  ultimate  chemical  elements. 
Another  kind  of  analysis,  called  ' '  proximate 
analysis,"  is  more  commonly  used,  which  sep- 
arates the  coal  into  four  parts,  viz. :  moisture,  vol- 
atile matter,  fixed  carbon,  and  ash.    The  method 


of  making  this  analysis  is  as  follows :  A  pulverized 
sample,  carefully  weighed,  is  heated  to  a  temper- 
ature not  exceeding  280°  Fahr.  until  it  is  found 
by  repeated  weighings  to  have  ceased  to  lose 
weight.  The  loss  m  weight  by  this  heating  is 
recorded  as  the  moisture.  The  heating  is  then 
continued  in  a  crucible  covered  with  a  lid,  and 
gradually  raised  in  temperature  to  a  red  heat, 
at  which  it  is  maintained  for  a  few  minutes,  or 
until  gas  ceases  to  be  driven  off.  The  crucible 
is  then  cooled  in  a  desiccator,  to  prevent  absorp- 
tion of  moisture  from  the  air,  and  weighed. 
The  loss  in  weight  by  this  heating  is  recorded  as 
volatile  matter.  The  crucible  is  then  raised  to 
a  white  heat,  with  the  lid  partly  open,  so  as  to 
admit  air  to  burn  the  coal,  and  the  heating  is 
continued  until  all  the  carbon  is  burned  away, 
leaving  nothing  but  the  ash,  which  after  cooling 
is  weighed,  and  the  difference  between  this  and 
the  previous  weight  is  recorded  as  fixed  carbon. 
The  fixed  carbon  being  thus  obtained  ' '  by  dif- 
ference ' '  the  sum  of  the  four  constituents  will 
add  up  to   100  per  cent.     The  analysis,  when 


51 


^ 


carefully  made,  is  practically  accurate  as  cegards 
the  moisture  and  ash,  but  the  percentages  of 
volatile  matter  and  of  fixed  carbon  may  be  a  few 
per  cent,  in  error,  as  they  appear  to  vary  with 
the  time  and  temperature  of  heating.  Some- 
times a  proximate  analysis  is  reported  giving 
the  percentage  of  sulphur,  the  sum  of  the  mois- 
ture, volatile  matter,  fixed  carbon,  sulphur,  and 
ash  adding  up  to  loo.  The  sulphur  is  not 
actually  determined  in  the  proximate  analysis, 
but  a  separate  determination  is  made  of  it  by 
the  ordinary  methods  of  the  chemist,  and  one- 
half  of  it  subtracted  from  the  volatile  matter 
and  one-half  from  the  fixed  carbon,  on  the 
supposition  that  half  of  the  sulphur  escaped 
during  each  of  the  two  heatings.  Some  chem- 
ists subtract  forty  per  cent,  of  the  sulphur  from 
the  volatile  matter  and  60  per  cent,  from  the  fixed 
carbon.  Others  report  the  four  constituents  as 
found  by  the  proximate  analysis,  adding  them  up 
to  100,  stating  the  sulphur  separately.  This  seems 
to  be  the  preferable  method.    Coals  that  are  high 


in  sulphur  are  apt  to  form  a  troublesome  clinker 
on  the  grates. 

The  proximate  analysis  is  of  great  value  for 
indicating  the  general  character  of  a  coal.  By 
dividing  the  percentages  of  volatile  matter  and 
fixed  carbon  each  by  their  sum  we  obtain  the 
percentages  of  each  in  the  ' '  combustible ' '  or 
coal  dry  and  free  from  ash.  These  percentages 
serve  to  identify  the  class  to  which  the  coal 
belongs,  as  anthracite,  semi-anthracite,  semi- 
bituminous,  bituminous,  or  lignite,  as  follows:  — 


Anthracite,    .     . 
Semi- Anthracite, 
Semi-Bituminous, 
Bituminous,  .     . 
Lignite,     .     .     . 


Fixed  Carbon 
per  cent,  of 
Combustible. 


100  to  92 
92  to  87 
87  to  75 
75  to  50 
below  50 


Volatile  Matter 
per  cent,  of 
Combustible. 


o  to  8 
8  to  13 
13  to  25 
25  to  50 
over  50 


The  class  of  coal  being  thus  determined,  the 
value  of  any  coal  in  a  class  may  be  further 
judged  by  the  percentages  of  moisture,  ash,  and 
sulphur. 


PROXIMATE  ANALYSES  AND   HEATING  VALUES  OF  AMERICAN  COALS. 


I 


Anthracite. 

Northern  coal  field,     .... 

East  Middle  coal  field,    .     .     . 

West  Middle  coal  field,   .     .     . 

Southern  coal  field,  .... 
A  nthracite  from  oiie  mine. 

Egg,    .     .      Screen  ^y^"-  i}i", 

Stove,       .     Screen  ij^"- I  J<(", 

Chestnut,      Screen  i/i"-   Yx", 

Pea,     .     .     Screen    Yj,"-    y", 

Buckwheat,  Screen  %"-  %" , 
Semi- A  nthracite. 

Loyalsock  field,       .     .     .     .     . 

Bernice  basin, 

Semi-B  itttininoiis . 

Broad  Top,  Pa., 

Clearfield  County,  Pa.,    .     .     . 

Cambria  County,  Pa.,      .     .     . 

Somerset  County,  Pa.,     .     .     . 

Cumberland,  Md.,       .... 

Pocahontas,  Va. 

New  River,  W.  Va.,  .... 
Bituminoiis, 

Connellsville,  Pa., 

Youghiogheny,  Pa. 

Pittsburg,  Pa., 

Jefferson  County,  Pa.,    .     . 

Middle  Kittanningseam,  Pa.,  . 

Upper Freeport  seam,Pa,andO. 

Thacker,  W.  Va., 

Jackson  County,  O.,  .     .     . 

Brier  Hill,  O. 

Hocking  Valley,  O.,  .     . 

Vanderpool,  Ky. ,    .     .  .     . 

Muhlenberg  County,  Ky.,    .     . 

Scott  County,  Tenn  ,  .... 

Jefferson  County,  Ala  ,  .     .     . 

Big  Muddy,  111., 

Mt.  Olive,  111., 

Streator,  111. 

Missouri, 

Lignites  and Lignitic  Coals. 

Iowa, 

Wyoming, 

Utah, 

Oregon  Lignite, 


Mois- 
ture. 

Volatile 
Matter. 

Fixed 
Carbon. 

Ash. 

Sul- 
phur. 

Heating 
Value  per 

lb.  coal, 
heat  units. 

Volatile 
Matter  per 

cent,  of 
combusti- 

Heating 
Value  per 
lb.  com- 
bustible. 

Theoretical 

Evaporation 

lbs.  water  from 

and  at  212°  per 

ble. 

heat  units. 

lb.  combustible 

3-42 

4-38 

83.27 

8.20 

•73 

13,160 

5.00 

14,900 

15.42       ^ 

3-71 

3.08 

86.40 

6 

22 

-58 

13-420 

3-44 

14,900 

15.42 

3-i6 

3-72 

81-59 

10 

65 

-50 

12,840 

4-36 

14,900 

15.42 

3-09 

4.28 

83.81 

8S.49 
83.67 
80.72 
79-05 
76.92 

8 

5 

10 
12 
14 
16 

iS 

66 
17 
67 
66 
62 

-64 

13,220 

4-85 

14,900 

15.42 

1.30 

8.10 

83-34 

6 

23 

1-63 

13,920 

8.86 

15.500 

16.05 

•65 

9.40 

83.69 

5 

34 

.91 

13,700 

10.98 

15.500 

16.05 

■79 

15.61 

77-30 

5 

40 

.90 

14,820 

17.60 

15,800 

16.36 

.76 

22.52 

71.82 

3 

99 

.91 

14,950 

24.60 

15,700 

16.25 

•94 

ig.2o 

71.12 

7 

04 

1.70 

14,450 

22.71 

15,700 

16.25 

1.58 

16.42 

71.51 

8 

62 

1.87 

14,200 

20.37 

15,800 

16.36 

1.09 

17.30 

73.12 

7 

75 

-74 

14,400 

19.79 

15,800 

16.36 

1. 00 

21.00 

74-39 

3 

03 

•58 

15,070 

22,50 

15,700 

16.25 

.85. 

17.88 

77.64 

3 

36 

.27 

15,220 

18.95 

15,800 

16.36 

1.26 

30.12 

59.61 

8 

23 

.78 

14,050 

34-03 

15.300 

15.84 

1.03 

36.50 

59-05 

2 

61 

.81 

14,450 

38-73 

15,000 

15-53 

I  37 

35-90 

52.21 

8 

02 

1.80 

13.410 

41.61 

14,800 

15-32 

1. 21 

32.53 

60.99 

4 

27 

1. 00 

14,370 

35-47 

15,200 

15-74 

1. 81 

35-33 

53-70 

7 

18 

1.98 

13,200 

40.27 

14,500 

15.01 

1-93 

35-90 

50.19 

9 

10 

2.89 

13.170 

43.59 

14,800 

15-32 

1.38 

35-04 

56.03 

6 

27 

1.28 

14,040 

39-33 

15,200 

15-74 

3.83 

32.07 

57.60 

6 

SO 

13,090 

35-76 

14,600 

15.11 

4.80 

34.60 

56.30 

4 

30 

13,010 

38.20 

14,300 

14.80 

6-59 

34-97 

48.85 

8 

00 

1-59 

12,130 

42. Si 

14,200 

14.70 

4.00 

34-10 

54.60 

7 

30 

12,770 

38.50 

14,400 

14.91 

4-33 

33-65 

55-50 

4 

95 

1-57 

13,060 

38.86 

1 4,400  (?) 

14.91 

1.26 

35-76 

53-14 

8 

I. So 

13,700 

34.17 

i5,ioo(?) 

15-63 

1-55 

34-44 

59-77 

2 

62 

1.42 

13,770 

37-63 

14,400  (?) 

14.91 

7.50 

30.70 

53-80 

8 

00 

12,420 

36-30 

14,700 

15-22 

11.00 

35-65 

37-IO 

13 

00 

10,490 

47.00 

13,800 

14.29 

12.00 

33-30 

40.70 

14 

00 

10,580 

45.00 

14,300 

14.80 

6.44 

37-57 

47-94 

8 

05 

12,230 

43-94 

14,300  (?) 

14.80 

8.45 

37.09 

35.60 

18 

86 

8,720 

51.03 

1 2,000  (?) 

12.42 

8.19 

38.72 

41-83 

II 

26 

10,390 

48.07 

I2,900(?) 

13-35 

9.29 

41-97 

44-37 

3 

20 

1. 18 

11,030 

48.60 

I2,6oo(?) 

13-04 

1.S.25 

42. 98 

33-32 

7 

" 

1.66 

8,540 

54.95 

ii,ooo(?) 

11-39 

■* 


52 


^ 


The  preceding  table  gives  the  proximate  anal- 
yses and  the  heating  values  of  a  number  of  Ameri- 
can coals.  The  analyses  are  selected  from  various 
sources  and  in  general  give  average  values  of 
many  samples.  The  heating  values  per  pound 
of  combustible  are  either  obtained  from  calori- 
metric  determinations  or  by  calculation  from  ulti- 
mate analyses,  except  those  marked  (?),  which 
are  estimated  from  the  heating  values  of  coals 
of  similar  composition.  The  theoretical  evapo- 
ration, in  the  last  column,  is  obtained  by  divid- 
ing the  heating  value  per  pound  of  combustible 
by  965.7,  the  number  of  heat  units  required  to 
evaporate  a  pound  of  water  at  212°  into  steam 
of  the  same  temperature.  The  heating  values 
per  pound  of  combustible  given  in  the  table, 
except  those  marked  (?)  are  probably  within 
3  per  cent,  of  the  average  actual  heating  values 
of  the  combustible  portion  of  the  coals  of  the 
several  districts,  the  combustible  being  defined 
as  the  coal  minus  its  moisture  and  ash.  When 
the  percentage  of  moisture  and  ash  in  any  given 
lot  of  coal  is  known  the  heating  value  per 
pound  of  coal  may  be  found  by  multiplying 
the  heating  value  per  pound  of  combustible  by 
the  difference  between  100  per  cent,  and  the 
sum  of  the  percentages  of  moisture  and  ash. 
The  figures  in  the  column  headed  "  Heating 
value  per  lb.  coal ' '  are  calculated  in  this  man- 
ner. 

Tables  giving  the  heating  values  per  pound 
of  coal  (not  combustible)  are  usually  of  little 
value,  for  published  analyses  are  often  of 
selected  samples,  containing  less  moisture  and 
ash  than  the  average  of  the  coal  mined,  and  the 
ash  is  apt  to  vary  greatly  in  different  portions  of 
a  mine.  The  combustible  portion  of  the  coal 
from  any  given  mine,  seam,  or  district,  however, 
especially  if  it  contains  over  60  per  cent,  of  fixed 
carbon,  is  usually  very  constant  in  heating  value. 

An  inspection  of  the  above  table  reveals  many 
interesting  facts.  The  semi-bituminous  coals 
of  Pennsylvania,  Maryland,  Virginia,  and  West 
Virginia  have  the  highest  heating  value  per 
pound  of  combustible  of  any  coals  in  the  United 
States,  and  are  remarkably  uniform,  the  whole 
range  of  their  heating  value  per  pound  of 
combustible  probably  being  within  the  limits 
of  15,500  and  16,000  heat  units.  They  are 
also  very  low  in  moisture,  ash,  and  sulphur,  so 
that  they  are  exceptionally  valuable  as  steam 
coals. 

The  anthracites  are  about  6  per  cent,  lower 
in  heating  value  per  pound  of  combustible,  due 
to  their  being  low  in  hydrogen.  The  ash  is 
usually  much  higher  than  the  figures  given  in 
the  table.     The  figures  for  moisture  given  in 


the  table  seem  rather  high,  other  analyses 
reporting  as  low  as  one  per  cent.,  but  in  pea  and 
buckwheat  coals  it  will  in  winter  time  sometimes 
run  as  high  as  7  per  cent.,  being  chiefly  surface 
moisture  contained  between  the  particles  of  coal, 
and  not  inclosed  in  the  coal  itself.  The  semi- 
anthracites  are  mined  in  a  limited  extent  of  terri- 
tory in  Pennsylvania.  Their  heating  value  is 
between  that  of  the  anthracites  and  the  semi- 
bituminous  coals. 

There  is  a  marked  dividing  line  between  the 
semi-bituminous  and  the  bituminous  coals  in 
the  United  States,  few  coals  being  known, 
except  in  the  South  and  in  Colorado,  which  are 
on  the  dividing  line  between  these  two  classes, 
or  containing  between  25  and  30  per  cent,  of 
volatile  matter  in  the  combustible.  The  bitumi- 
nous coals  are  of  great  variety.  We  have  first 
the  coals  mined  in  Fayette,  Westmoreland, 
Indiana,  and  Jefferson  counties  in  Pennsylvania, 
including  the  Connellsville  and  the  Youghio- 
gheny  coals,  lying  just  west  of  the  semi-bitumi- 
nous region,  which  includes  Somerset,  Cambria, 
and  Clearfield  counties.  These  coals  are  low 
in  moisture  and  sulphur,  moderately  low  in  ash, 
and  their  heating  value  usually  ranges  between 
15,000  and  15,300  heat  units  per  pound  of  com- 
bustible. The  Thacker,  W.  Va.,  coal  is  also  of 
this  class.  Next  come  the  coals  of  the  western 
tier  of  counties  in  Pennsylvania,  belonging  to  the 
Pittsburg,  Upper  Freeport,  and  Middle  Kittan- 
ning  seams,  which  have  a  heating  value  between 
14,200  and  15,000  heat  units  per  pound  of  com- 
bustible. These  coals  are  also  low  in  moisture, 
but  some  of  them  are  rather  high  in  sulphur. 

Passing  further  west  we  have  the  Ohio  coals, 
characterized  by  higher  percentages  of  moisture 
than  the  Pennsylvania  coals,  and  higher  oxygen 
as  shown  by  the  ultimate  analysis.  Their  heat- 
ing value  ranges  from  14,200  to  14,600  heat  units 
per  pound  of  combustible.  The  Vanderpool, 
Ky.,  coal,  given  in  the  table,  also  appears  to 
belong  to  this  class.  The  three  Ohio  coals 
given  in  the  table  have  from  3.83  to  6.59  per 
cent,  moisture,  and  it  is  to  be  noted  that  this  is 
not  surface  moisture  but  that  found  in  a  lump 
of  apparently  dry  coal.  All  of  the  bituminous 
coals  contain  moisture  in  the  same  way  that 
wood  contains  it,  and  they  are  hygroscopic, 
that  is,  if  dried  in  an  oven  they  will  afterwards 
absorb  moisture  from  the  atmosphere.  The 
chief  difference  in  the  character  of  different 
Western  bituminous  coals  is  in  the  amount  of 
moisture  that  they  contain,  some  of  the  Illinois 
coals  containing  as  high  as  15  per  cent.,  which 
may  be  driven  off  by  heating  them  to  240°  to  280° 
Fahr.,  but  they  will  absorb  all  of  this  moisture 


53 


•^ 


again  on  prolonged  exposure  to  the  air.  The 
Indiana  coals  contain  much  more  moistur'e  than 
the  Ohio  coals,  but  less  than  the  Illinois  coals. 
The  sample  whose  analysis  is  given  in  the  table 
is  about  an  average  of  the  Indi- 
ana coals. 

The  Illinois  coals  vary  con- 
siderably in  constitution,  the 
Big  Muddy  coal,  mined  in  the 
southern  part  of  the  State, 
being  of  quite  a  different  class 
from  those  mined  in  the  central 
and  northern  parts,  of  which 
the  Mi.  Olive  and  the  Streator 
coals  are  types.  This  coal  has 
about  7.5  per  cent,  moisture, 
and  its  heating  value  is  about 
14,700  heat  units  per  pound  of 
combustible.  It  is  also  low  in 
ash,  causing  it  to  rank  equal  to 
a  good  Ohio  coal.  The  coals 
from  the  central  and  northern 
parts  of  the  State  run  from  10 
to  15  per  cent,  of  moisture, 
many  of  them  are  very  high  in 
sulphur  and  ash,  and  they  are 
also  high  in  volatile  matter,  a 
large  part  of  which  is  oxygen. 
Their  heating  value  per  pound 
of  combustible  has  a  range  of 
from  about  13,500  to  14,500  heat 
units,  averaging  about  14,200. 
The  coals  of  Kentucky  ap- 
pear to  be  similar  to  the  Ohio 
coals,  and  those  of  Tennessee 
and  Alabama  to  those  of  west- 
ern Pennsylvania.  Many  of 
them  are  very  much  higher  in 
ash  than  the  figures  given  in 
the  table,  and  it  is  probable 
that  they  vary  in  volatile  matter 
and  in  heating  value  in  the  dif- 


■m 

1 

ferent  districts  within  the  range  of  the  various 
coals  of  western  Pennsylvania  and  Ohio. 

West  of  the  Mississippi  the  coals  are  gener- 
ally ver}-  high  in  moisture  and  ash,  and  their  vola- 
tile matter  is  high  in  oxygen,  characterizing  them 
as  lignites,  but  there  are  exceptions  to  this  rule 
in  Arkansas  and  Colorado,  in  which  the  char- 
acter of  the  coals  varies  through  the  whole 
range  between  anthracite  and  lignite. 

The  relative  value  of  different  fuels  is  largely 
a  question  of  locality  and  transportation.  For 
instance,  in  some  parts  of  Central  America  they 
burn  rosewood  under  their  boilers,  because  it  is 
cheaper  than  coal ;  while  a  few  years  ago  in  the 
West  it  was  found,  during  a  coal  famine,  that  In- 
dian corn  was  the  cheapest  fuel  they  could  burn. 
In  some  places  they  burn  manure  only.  The 
Babcock  &  Wilcox  boilers  of  Chicago  cable 
railways  were  for  a  long  tinie  run  regularly  on 
the  offal  from  the  stables  of  the  horse  roads,  a 
very  small  proportion  of  coal  being  used  to  keep 
it  alight. 

"Slack,"  or  the  screenings  from  coal,  when 
properly  mixed, — anthracite  and  bituminous, — 
and  burned  by  means  of  a  blower  on  a  grate 
adapted  to  it,  is  nearly  equal  in  value  of  com- 
bustible to  coal,  but  its  percentage  of  refuse  is 
greater. 

The  effective  value  of  all  kinds  of  wood  per 
pound,  when  dry,  is  substantially  the  same. 
This  is  usually  estimated  at  0.4  the  value  of 
the  same  weight  of  coal.  The  following  are  the 
weights  and  comparative  value  of  different 
woods  by  the  cord :  — 


Kind  of  Wood. 

Weight. 

Kind  of  Wood. 

Weight. 

Hickory,  Shellbark 
Hickory,  Red  heart 
White  Oak     .     .     . 
Red  Oak  ...     . 
Spruce       .... 
New  Jersey  Pine   . 

4469 

3705 
3821 

3254 
2325 
2137 

Beech   .     .     .    .     . 
Hard  Maple .     .     . 
Southern  Pine   .     . 
Virginia  Pine     .     . 
Yeilovv  Pine  .    .     . 
White  Pine   .     .     . 

3126 

2878 

3375 
2680 
1904 
1868 

Boiler  House  and  Chimney  for  Babcock  &  Wilcox  Boilers, 
2000  H.P.,  with  Artificial  Blast,  Economizer,  etc. 


Much  was  said  at  one  time  about  the  wonderful 
saving  which  could  be  expected  from  the  use 
of  petroleum  for  fuel.     This  is  all  a  myth,  and  a 
moment's  attention  to  facts  is  sufficient  to  con- 
vince   anyone   that  no  such  possibility  exists. 
Petroleum  has  a  heating  capacity,  when  fully 
burned, equal  to  from  21, 000 to  22,000  B.T.U. 
per  pound,  or  say  50  per  cent,  more  than 
coal.     But,  owing  to  the  ability  to  burn  it 
%n^  with  less  losses,  it  has  been  found  through 
extended  experiments  by  the  pipe  lines  that 
under  the  same  boilers,  and  doing  the  same 
work,  a  pound  of  petroleum  is  equal  to  i.S 
pounds  of  coal.     The  experiments  on  loco- 
motives in  Russia  have  shown  practically 
the  same  value,  or  1.77.     Now,  a  gallon  of 


54 


petroleum  weighs  6.7  pounds  (though  the  stan- 
dard buying  and  selling  weight  is  6.5  pounds), 
and  therefore  an  actual  gallon  of  petroleum  is 
equivalent  under  a  boiler  to  twelve  pounds 
of  coal,  and  190  standard  gallons  are  equal 
to  a  gross  ton  of  coal.  It  is  very  easy  with  these 
data  to  determine  the  relative  cost.  At  the 
wells,  if  the  oil  is  worth  say  two  cents  a  gallon, 
the  cost  is  equivalent  to  I3. 80  per  ton  for  coal  at 
the  same  place,  while  at  say  three  cents  per  gal- 
lon, the  lowest  price  at  which  it  can  be  delivered 
in  the  vicinity  of  New  York,  it  costs  the  same  as 
coal  at  I5.70  per  ton.  The  Standard  Oil  Co. 
estimate  that  173  gallons  are  equal  to  a  gross  ton 
of  coal,  allowing  for  incidental  savings,  as  in 
grate  bars,  carting  ashes,  attendance,  etc. 

Sawdust  can  be  utilized  for  fuel  to  good  ad- 
vantage by  a  special  furnace  and  automatic  feed- 
ing devices.  Spent  tan  bark  is  also  used,  mixed 
with  some  coal,  or  it  may  be  burned  without  the 
coal  in  a  proper  furnace.  Its  value  is  about  one- 
fourth  that  of  the  same  weight  of  wood,  as  it 
comes  from  the  press,  but  when  dried  its  value 
is  about  85  per  cent,  of  the  same  weight  of  wood 
in  same  state  of  dryness. 

Bagasse,  the  refuse  of  sugar  cane,  after  being 
dried  in  the  sun,  is  largely  employed  in  Cuba. 
Its  value  is  about  equal  to  the  same  weight 
of  pine  wood,  in  the  same  state  of  dryness.  As 
it  comes  from  the  mill  it  contains  from  50  to 
80  per  cent,  of  water,  in  which  state  it  may  be 
burned  in  Cook's  Bagasse  Furnace,  under  Bab- 
cock  &  Wilcox  Boilers,  with  a  result  nearly  or 
quite  equal  to  that  of  the  dried  bagasse  under 
ordinary  boilers,  thus  saving  the  large  expense  of 
drying  it. 

It  has  been  estimated  that  on  an  average  one 
pound  of  coal  is  equal,  for  steam-making  pur- 
poses, to  2  pounds  dry  peat,  2%  to  2%  pounds 
dry  wood,  2>^  to  3  pounds  dried  tan  bark,  2% 
to  3  pounds  sun-dried  bagasse,  2^  to  3  pounds 
cotton  stalks,  3X  to  3^  pounds  wheat  or  bar- 
ley straw,  5  to  6  pounds  wet  bagasse,  and  6  to  8 
pounds  wet  tan  bark. 

Natural  gas  varies  in  quality,  but  is  usually 
worth  2  to  2^  times  the  same  weight  oi  coal,  or 
about  30,000  cubic  feet  are  equal  to  a  ton  of  coal. 


will  enable  the  temperature  to  be  judged  by  the 
appearance  of  the  fire: — 


TEMPERATURE  OF  FIRE. 

By  reference  to  the  table  of  combustibles,  it 
will  be  seen  that  the  temperature  of  the  fire  is 
nearly  the  same  for  all  kinds  of  combustibles, 
under  similar  conditions.  If  the  temperature  is 
known,  the  conditions  of  combustion  may  be  in- 
ferred.    The  following  table,  from  M.  Pouillet, 


Appearance. 

Temp.  Fah. 

Appearance. 

Temp.  Fah. 

Red,  just  visible, 
"      dull,  .     .     . 
"      Cherry,  dull, 
full, 
"          "        clear. 

977° 
1290 
1470 
1650 
1830 

Orange,  deep, 
"        clear, 

White  heat,  . 
"  bright, 
"      dazzling. 

2010° 
2 1  go 
2370 
2550 
2730 

To  determine  temperature  by  fusion  of  met- 
als, etc.: — 


Sub- 
stance. 

Temp. 
Fah. 

Metal. 

Temp. 

Fah. 

Appearance. 

Temp. 
Fah. 

Spermaceti, 
W'ax,  white, 
Sulphur,  . 
Tin,     .     . 
Bismuth, 

120° 

154 

239 

455 

5'8 

Lead,      . 
Zinc, 

Antimony, 
Aluminum, 
Brass,    . 

610° 
700 
810 
1 160 
1650 

Silver,  pure, 
Gold  Coin,   . 
Iron  Cast,  med 
Steel,  .     .     . 
Wrought  Iron, 

1830° 

2156 

2010 

2550 
2910 

CONDENSERS. 

The  condensation  of  steam  in  a  separate  cham- 
ber from  the  engine  cylinder  instead  of  by  a  spray 
of  water  injected  into  the  cylinder  itself  after  the 
steam  piston  had  completed  its  stroke,  was  an 
invention  of  James  Watt,  in  1765,  for  which  he 
received  letters  patent  in  1769.  It  was  the  first 
step  in  the  history  of  the  steam  engine  in  the  di- 
rection of  increased  efficiency  from  the  atmos- 
pheric engines  in  use  at  that  time,  towards  the 
present  era  of  high  steam  pressure  and  multiple 
expansion  condensing  engines. 

Where  a  sufficient  quantity  of  water  suitable 
for  boiler  feeding  purposes  is  available,  the  jet 
condenser, being  the  simplest  and  easiest  to  oper- 
ate, is  preferable.  Where,  however,  water  suit- 
able for  boiier  feeding  is  not  available,  a  surface 
condenser  may  be  used.  In  this  type  the  steam 
is  condensed  in  a  condensing  chamber  on  the  sur- 
face of  tubes  through  which  cold  water  is  circu- 
lating, and  the  distilled  water  so  furnished  may 
be  again  fed  to  the  boilers.  Where  any  consid- 
erable amount  of  cylinder  oil  is  used,  some  pro- 
vision must  be  made  with  surface  condensers  to 
remove  this  oil  before  the  water  is  fed  to  the 
boilers.  With  either  type  the  quantity  of  water 
to  be  circulated  through  the  condenser  should  be 
from  20  to  40  times  the  quantity  of  steam  to  be 
condensed,  depending  upon  the  temperature  of 
the  water  available  for  condensing  purposes. 

American  condenser  manufacturers  have  re- 
cently introduced  several  types  of  self-cooling 
condensers  by  which  the  hot  water  delivered 
from  the  condenser  pumps  can  be  cooled  and  re- 
used, so  that  with  water  sufficient  in  quantity  for 
boiler  feed  purposes  onl}^,  the  plant  may  be  lo- 
cated at  any  convenient  point,  and  still  retain  the 
fuel  saving  and  other  benefits  of  high  steam  pres- 
sures and  condensers. 


*i^ 


55 


BURNING  GREEN  BAGASSE 

The  refuse  from  sugar  cane,  after  it  has  left 
the  grinding  rolls,  contains  usually  from  25  to  40 
per  cent,  of  woody  fiber  and  from  6  to  9  per 
cent,  of  sugar,  while  the  balance,  respectively 
66  to  54  per  cent. ,  is  water.  In  this  condition  it 
is  not  combustible  in  ordinary  furnaces,  for 
which  purpose  it  requires  to  be  sun-dried, 
which  process  removes  from  eight  to  nme  tenths 
of  the  moisture  and  nearly  all  the  sugar  through 
fermentation.  This  sugar  itself  is  an  excellent 
fuel,  and  if  it  could  be  utilized  as  such  would 
be  nearly  sufficient  to  evaporate  the  water  in 
which  it  is  dissolved,  so  that  it  is  probable  that 
the  process  of  drying  by  natural  means  destroys 
more  fuel  than  sufificient  to  do  the  drying  includ- 
ing that  wasted  in  the  several  handlings.  If, 
therefore,  the  green  bagasse  can  be  burned 
direct  from  the  mill  it  should  give  as  good 
results  as  when  dried. 

Cook's  Automatic  Apparatus  accompHshes 
this  result,   burning  the  bagasse  automatically 
direct  from  the  sugar  mill,  with  a  saving  of  the 
large  number  of  men,  carts,  and  oxen  required 
for  spreading,  drying,  gathering,  and  firing  it  in 
a  dry  state.     It  also  secures  far  better  combus- 
tion than  can  be  had  with  the  best  hand  firing, 
with  no  smoke,  little  refuse,  and  a  greatly  in- 
creased  evaporative   capacity.     An  element  of 
additional    economy    consists    in   utilizing  the 
waste  heat  escaping  to  the  chimney  for  heating 
the  blast.     This  hot  blast  is  peculiarly  efficient 
in  burning  wet  fuel,  because  of  the  greatly  in- 
creased  capacity   of   the  hot  air  for  absorbing 
moisture,  and  thus  partially  drying  the  ba- 
gasse before  burning.     Air  at  200°  tem- 
perature has  over  two  hundred 
times  the  capacity  for  mois- 
ture that  the  same  air 
has  at  60°,  and  the  - 


air  required  for  the  combustion  of  the  fuel  in  the 
bagasse,  if  forced  into  the  furnace  at  300°  tem- 
perature, will  carry  away  the  excess  of  moisture 
in  the  fuel  without  other  heat  than  that  itself 
contains.  Therefore,  if  the  blast  is  heated  by 
the  waste  gases  to  that  temperature,  it  secures 
the  full  value  of  the  fuel  for  steam  making,  the 
same  as  if  it  were  dried  before  it  was  delivered 
to  the  furnace.  These  considerations  explain 
the  fact  that  where  these  burners  have  been 
erected  they  have  always  brought  about  a  large 
reduction  in  the  supplementary  fuel  required 
with  dry  bagasse,  besides  giving  more  and 
steadier  steam  pressure.  In  a  well  arranged  plan- 
tation the  bagasse  is  sufficient  without  other  fuel. 

The  furnace  of  Cook's  apparatus  consists  in 
an  oven  of  brick  having  a  smaller  chamber  be- 
neath, into  which  the  blast  previously 
heated  is  introduced  through  nu- 
merous perforations  in  the  walls. 
Openings  in  the  walls  of  the  oven 
permit  the  escape  of  the  gases  of 
combustion  to  the  boilers.  On  their 
way  to  the  chimney  these  gases 
pass  tubular  heaters,  through  which  a 
fan  forces  the  blast  en  route  to  the 
burner,  thus  returning  a  large  part  of 
the  waste  heat  to  the  furnace  and 
securing  an  exceedingly  high  tem- 
perature therein. 

The  furnaces  require  to  be  cleaned 
once  in  24  hours,  when  the  refuse 
from  250  tons  of  bagasse  makes 
about  four  wheelbarrow  loads,  in  the 


Side  View  of  Cook's  Automatic  Apparatus  for  Burning  Green  Bagasse  with  Babcock  &  Wilcox  Boilers,  at  Yngenio  Senado. 


57 


^ 


form  of  a  vitreous  mass,  evidencing  the  intense  heat  attained.  This 
high  temperature  is  readily  absorbed  by  the  Babcock  &  Wilcox  boil- 
ers without  injury  to  the  heating  surface,  but  it  is  not  considered 
safe  to  apply  it  to  other  boilers  having  thicker  heating  surface  and  a 
less  perfect  circulation  of  water. 

The  bagasse  is  fed  to  the  furnaces  automatically  by  an  arrangement 
of  carriers  which  receive  it  from  the  rolls  and  distribute  it  equably  to 
the  different  furnaces,  where  more  than  one  is  required,  dumping  any 
surplus  upon  cars,  where  it  is  stored  for  use  when  the  mill  is  not  grind- 
ing. The  number  of  attendants  required  is  reduced  to  a  minimum, 
every  operation  being  automatic.  At  Yngenio  Senado  two  of  these 
burners  reduce  the  number  of  men  employed  from  250  to  60,  besides 
the  saving  in  wood  and  teams,  the  better  supply  of  steam,  the  ability 
to  grind  during  rainy  weather,  and  the  total  absence  of  risk  of  fires. 
As  a  rule,  the  cost  of  the  apparatus  is  repaid  in  the  first  crop. 

Four  of  Cook's  apparatus  with  Babcock  &  Wilcox  boilers  have  now 
taken  oflf  six  crops  each  in  Louisiana  with  no  repairs  or  stoppages, 
and  with  perfect  success  in  every  case.  Forty  burners  in  Cuba 
the  last  season  worked  through  the  entire  crop  successfully  without  the 
least  stoppage  or  trouble.  No  wood  was  required 
after  the  first  starting,  the  spare  bagasse  serving  to 
light  the  burner  after  stopping  for  cleaning,  as  well  as 
to  keep  it  running  when  the  mill  was  not  grinding. 
Burning  green  bagasse  with  economy  and  efficiency  is, 
therefore,  no  longer  a  problem,  but  an  assured  success. 

Cook's  Apparatus  is  the  subject  of  numerous 
patents  in  all  sugar-producing  countries.  These 
patents,    all  of  which   are  owned,  or  controlled,  by 


^; 


the  Babcock  &  Wilcox  Company,  cover  all  the  pecul- 
iarities which  distinguish  this  process  and  apparatus 
from  the  previous  crude  attempts  to  burn  green  ba- 
gasse. Among  these,  are  the  arrangement  of  several 
boilers  for  one  burner;  the  construction  of  the  furnace 
without  grate  bars;  the  hot  blast  in  numerous  jets, 
applied  to  a  bagasse  burner,  and  the  method  of  heat- 
ing the  same;  "the  method  of  dividing  the  bagasse 
automatically  between  several  burners;  the  improved 
carriers;  the  storing  of  surplus  bagasse  for  use 
when  the  mill  is  stopped  temporarily  ;  the  arrange- 
ment of  the  bagasse-fired  boilers  so  that  they  may  be 


fired  with  other  fuel  in  the  ordinary  manner  when  the 
mill  is  not  grinding;  and  numerous  other  important 
details.  It  is  the  only  apparatus  which  will  effectually 
take  care  of  the  bagasse  direct  from  the  mill.  During 
the  season  of  1891-92  there  were  sixty- three  Cook's 
furnaces  on  the  island,  automatically  caring  for  and 
consuming  the  bagasse  from  23,000  tons  of  cane  daily. 


59 


4 


>"^ 


HORSE-POWER  OF  BOILERS. 

Strictly  speaking,  there  is  no  such  thing  as 
"horse-power  "  to  a  steam  boiler;  it  is  a  meas- 
ure applicable  only  to  dynamic  effect.  But  as 
boilers  are  necessary  to  drive  steam  engines,  the 
same  measure  applied  to  steam  engines  has  come 
to  be  universally  applied  to  the  boiler,  and  can- 
not well  be  discarded.  In  consequence,  how- 
ever, of  the  dift'erent  quantity  of  steam  necessary 
to  produce  a  horse-power,  with  dift'erent  engines, 
there  has  been  great  need  of  an  accepted  stand- 
ard by  which  the  amount  of  boiler  required  to 
provide  steam  for  a  commercial  horse-power  may 
be  determined. 

This  standard,  as  fixed  by  Watt,  was  one  cubic 
foot  of  water  evaporated  per  hour  from  212°  for 
each  horse-power.  This  was,  at  that  time,  the 
requirement  of  the  best  engine  in  use.  At  the 
present  time.  Professor  Thurston  estimates,  that 
the  water  required  per  hour,  per  horse-power,  in 
good  engines,  is  equal  to  the  constant  200,  di- 
vided by  the  square  root  of  the  pressure,  and  that 
in  the  best  engines  this  constant  is  as  low  as  150. 
This  would  give  for  good  engines,  working  with 
64  lbs.  pressure,  25  lbs.  water,  and  for  the  best 
engines  working  with  100  lbs.,  only  15  lbs.  water 
per  hourly  horse-power. 

The  extensive  series  of  experiments,  made 
under  the  direction  of  C.  E.  Emery,  M.E.,  at  the 
Novelty  Works,  in  1866-8,  and  published  by 
Professor  Trowbridge,  show,  that  at  ordinary 
pressures,  and  with  good  proportions,  non-con- 
densing engines  of  from  20  to  300  H.P.  required 
only  from  25  to  30  lbs.  water  per  hourly  horse- 
power, in  regular  practice. 

The  standard,  therefore,  adopted  by  the  judges 
at  the  late  Centennial  Exhibition,  of  30  lbs. 
water  per  hour,  evaporated,  at  70  lbs.  pressure, 
from  100°,  for  each  horse-power,  is  a  fair  one  for 
both  boilers  and -engines,  and  has  been  favor- 
abl}'  received  by  the  Am.  Soc.  of  Mech.  Engineers 
and  by  steam  users,  but  as  the  same  boiler  may 
be  made  to  do  more  or  less  work  with  less  or 
greater  economy,  it  should  be  also  required  that 
the  rating  of  a  boiler  be  based  on  the  amount  of 
water  it  will  evaporate  at  a  high  economical  rate. 

For  purposes  of  econom}' 
the  amount  of  heating  surface 
should  never  be  less  than  one, 
and  generally  not  more  than 
two,  square  feet,  for  each 
5,000  British  thermal  units  to 
be  absorbed  per  hour,  though 
this  depends  somewhat  on 
the  character  and  location  of 
such  surface.  The  range 
given  above  is  believed  to  be 


sufficient  to  allow  for  the  different  conditions  in 
practice,  though  a  far  greater  range  is  frequently 
employed.  As,  for  instance,  in  torpedo  boats, 
where  everything  is  sacrificed  to  lightness  and 
power,  the  heating  surface  is  sometimes  made  to 
absorb  12,000  to  15,000  B.T.U.  per  square  foot 
per  hour,  while  in  some  mills,  where  the  pro- 
prietor and  his  advisers  have  gone  on  the  princi- 
ple that  "too  much  is  just  enough,"  a  square 
foot  is  only  required  to  absorb  1000  units  or  less 
per  hour.     Neither  extreme  is  good  economy. 

Square  feet  of  heating  surface  is  no  criterion 
as  between  different  styles  of  boilers  —  a  square 
foot  under  some  circumstances  being  many  times 
as  efficient  as  in  others;  but  when  an  average 
rate  of  evaporation  per  square  foot  for  any  given 
boiler  has  been  fixed  upon  by  experiment,  there 
is  no  more  convenient  way  of  rating  the  power  of 
others  of  the  same  style.  The  following  table 
gives  an  approximate  list  of  square  feet  of  heat- 
ing surface  per  H.P.  in  different  styles  of  boilers, 
and  various  other  data  for  comparison  :  — 


Type  of  Boiler. 

Square  feet 

Heating  Si 

face  for 

One  H.P 

5?  >< 

.>  >,.g 

0 
< 

Water-tube,  .     . 

10  to  12 

.3 

1. 00 

1. 00 

Isherwood. 

Tubular,    .     .     . 

14  to  18 

.25 

.gi 

.50 

" 

Flue,     .... 

8  to  12 

•4 

•79 

.25 

Prof.  Trow- 

Plain Cylinder,  . 

6  to  ID 

•S 

.6q 

.20 

bridge. 

Locomotive, .     . 

12  to   16 

.275 

.8^ 

■55 

Vertical  Tubular, 

15  to  20 

•25 

.80 

.60 

A  horse-power  in  a  steam  engine  or  other 
prime  mover  is  550  lbs.  raised  i  foot  per  second, 
or  33,000  lbs.  I  foot  per  minute. 


HORSE-POWER  OF  DIFFERENT  NATIONS. 

Most  nations  have  a  standard  for  power  simi- 
lar to,  and  generally  derived  from.  Watt's  '  'horse- 
power," but,  owing  to  different  standards  of 
weights  and  measures,  these  are  not  identical, 
though  the  greatest  differences  amount  to  less 
than  I  yi  per  cent.  The  following  table  gives  the 
standard  horse-power  for  each  nation,  in  kilo- 
grammeters  per  second,  and  in  foot-pounds  per 
second,  expressed  in  the  foot  and  pound  stand- 
ard in  each  country: — 


TABLE 

OF  STANDARD 

HORSE-POWER  FOR  DIFFERENT  NATIONS. 

S  „-j 

^•S  J 

•s  . 

c  C  " 

g    -S  . 

gfd 

•S'S  0 

""So 

cu   W)§  u 

■n  3  J! 

Country. 

hpS  " 

"^  0  ■" 

><  0  " 

M    0    ■" 

>  g  " 

■s  °  f 

m^- 

"^^1 

fc 

fc 

li. 

we 

fe 

^ 

France  and  1 
Baden,      j 

75 

500 

529.68 

521.58 

477-93 

513-53 

542.47 

423.6S 

Saxony,   .     . 

75-045 

500.30 

530 

523-89 

478.22 

513-84 

542.  So 

42393 

Wurtemberg, 

75.240 

501.36 

531.12 

525 

479-23 

514.92 

543-95 

424-83 

Prussia,  .     . 

75-325 

502.17 

531-97 

525-85 

480 

515-75 

544-82 

425.51 

Hanover,     . 

75-361 

502.41 

532-23 

526.10 

480.23 

516 

545-08 

425.72 

England, 

76.041 

506.94 

537-03 

530.84 

484.56 

520.65 

550 

429.56 

Austria,  .     . 

76.119 

507.46 

437-58 

531-39 

485.06 

521.19 

550.57 

430 

•i^ 


61 


■^H 


4--^ 


^ 


BOILERS  IN  IRON  AND  STEEL  WORKS. 

The  requirements  of  a  steam  boiler  in  an  iron 
or  steel  works  are  more  severe  than  in  any  other 
establishment,  with  possibly  the  exception  of  a 
sugar  plantation.  The  heat  applied  to  the  boiler 
is  not  only  intense,  but  flu6luating.  The  utmost 
possible  amount  of  work  may  be  required  from 
the  boiler  for  one  hour,  and  scarcely  any  work 
the  next,  while  in  many  iron  works  too  little 
attention  is  paid  to  the  boiler-house  by  the  man- 
agement, it  being  left  to  the  care  or  neglect  of 


This  boiler  possesses  for  this  purpose  the  ad- 
vantages of  safety  and  economy.  The  intense 
heat  of  the  gases  from  a  puddling  furnace  is  very 
destructive  of  thick  plates  and  riveted  joints, 
causing  frequent  violent  explosions  in  boilers  so 
heated.  The  thin  tubes,  and  rapid  circulation, 
in  these  boilers  render  them  less  liable  to  damage 
from  the  high  temperature,  and  the  arrangement 
of  heating  surface  secures  a  fuller  absorption  of 
the  waste  heat.  Should  a  tube  burn  out,  no  se- 
rious explosion  can  occur. 


Section  of  Babcock  &  Wilcox  Boiler  fitted  with  Kennedy  Burner  for  burning  Blast  Furnace  Gas. 


incompetent  men.  There  is,  also,  frequently  a 
lack  of  sufficient  boiler  capacity,  and  in  conse- 
quence the  boilers  are  driven  at  a  rate  which  is 
both  wasteful  of  fuel  and  destructive  to  heating 
surfaces. 

An  extended  experience  with  the  Babcock  & 
Wilcox  boilers  in  iron  and  steel  works  extending 
over  many  years,  under  a  variety  of  conditions, 
in  connection  with  heating,  puddling,  and  blast 
furnaces,  utilizing  the  waste  heat,  has  shown 
their  adaptability  and  superiority  for  such  work. 


Some  establishments  place  their  boilers  over 
the  furnaces,  as  shown  in  the  cut,  while  others 
place  them  at  the  side  of  the  furnace,  or  in  the 
rear.  One  advantage  of  this  boiler,  especially 
for  double  puddling  and  large  heating  furnaces, 
is  that  a  much  larger  amount  of  heating  surface 
can  be  placed  over  a  furnace  than  can  be  done 
with  the  boilers  ordinarily  used  for  this  purpose, 
thereby  giving  greater  economy  of  fuel  with  less 
cost  of  erection.  At  the  Carron  Iron  Works, 
near  Glasgow,    Scotland,    the  Lucy  Furnaces, 


^ 


63 


It 


Pittsburgh,  Pa.,  and  elsewhere,  these  boilers  are 
fired  with  the  waste  gases  of  the  blast  furnaces 
with  marked  success.  The  combustion  of  the 
gas  is  perfect;  the  boilers  develop  much  more 
than  their  rated  capacity;  and  the  dust  contained 
in  the  gas  has  given  no  trouble.  The  manager  of 
the  Lucy  Furnaces  says:  — 

"They  are  very  free  steamers,  easily  cleaned, 
and  will  do  a  given  amount  of  work  on  very  much 
less  gas  than  our  cylinder  or  two-flue  boilers. 
They  have  cost  nothing  for  repairs." 


WEIGHT  AND  VOLUME  OF  AIR. 

A  cubic  foot  of  air  at  60°  and  under  average 
atmospheric  pressure,  at  sea  level,  weighs  536 
grains,  and  13.06  cubic  feet  weigh  one  pound. 
Air  expands  or  contracts  an  equal  amount  with 
each  degree  of  variation  in  temperature.  Its 
weight  and  volume  at  any  ternperature  under  30 
inches  of  barometer  may  be  found  within  less 
than  one-half  of  one  per  cent,  by  the  following 
formula,  in  which  W  =  weight  in  pounds  of  one 
cubic  foot,  V  =:  volume  in  cubic  feet,  per  pound, 


Babcock  &  Wilcox  Boilers  over  Puddling  Furnace. 


In  rolling  mills  doing  the  heaviest  and  most 
irregular  kind  of  work,  the  success  of  these  boil- 
ers has  been  equally  encouraging,  and,  in  a 
number  of  the  Bessemer  Steel  Works,  they  are 
supplying  steam  to  reversing  engines  rolling  steel 
ingots  in  two  high  trains,  while  several  large 
plants  supply  power  for  rolling  rods,  bar  iron, 
rails  and  beams,  and  drawing  wire.  The  names 
of  many  extensive  iron  and  steel  works,  in 
some  of  which  large  plants  have  been  in  use  for 
years,  will  be  given  on  application. 


and  r  =  absolute  temperature,  or  460°  added 
to  that  by  the  thermometer,  =  /  +  460. 

W  =  42  V  =  — 

T  40 

For  any  condition  of  pressure  and  temperature 
the  following  formulas  are  very  nearly  exact : — 
P 


W 


V  = 


2.71/ 


/  =  2.7i  V/ — 460 


in  which  p  is  pressure  above  absolute  vacuum. 
The  same  formulas  answer  for  any  other  gas  by 
changing  the  co-efificient. 


65 


•¥"i 


CHIMNEYS 

Chimneys  are  reciuirecl  for  two  pur- 
poses —  I  St,  to  carry  off  obnoxious  gas- 
es ;  2d,  to  produce  a  draft,  and  so 
facilitate  combustion.  The  first  re- 
quires size,  the  second  height. 

Each  pound  of  coal  burned  yields 
from  13  to  30  pounds  of  gas,  the  vol- 
ume of  which  varies  with  the  temper- 
ature. 

The  weight  of  gas  to  be  carried  off  by 
a  chimney  in  a  given  time  depends  upon 
three  things  —  size  of  chimney,  velocity 
of  flow,  and  density  of  gas.  But  as 
the  density  decreases  directly  as  the  ab- 
solute temperature,  while  the  velocity 
increases,  with  a  given  height,  nearly  as 
the  square  root  of  the  temperature,  it 
follows  that  there  is  a  temperature  at 
which  the  weight  of  gas  delivered  is 
a  maximum.  This  is  about  550°  above 
the  surrounding  air.  Temperature, 
however,  makes  so  little  difference, 
that  at  550°  above,  the  quantity  is  07ily 
four  per  cent,  greater  than  at  300°. 
Therefore,  height  and  area  are  the  only 
elements  necessary  to  consider  in  an 
ordinary  chimney. 

The  intensity  of  draft  is,  how- 
ever, independent  of  the  size,  and  de- 
pends upon  the  difference  in  weight  of 
the  outside  and  inside  columns  of  air, 
which  varies  nearly  as  the  product  of 
the  height  into  the  difference  of  tem- 
perature. This  is  usually  stated  in  an 
equivalent  column  of  water,  and  may 
vary  from  o  to  possibly  2  inches. 

After  a  height  has  been  reached  to 
produce   draft,  of    sufficient   intensity 
to  burn  fine,  hard  coal,  provided  the 
area  of  the  chimney  is  large  enough, 
there  seems  no  good  mechanical  reason 
for  adding  further  to  the  height,  what- 
ever the  size  of  the  chimney  requir- 
ed.    Where  cost  is  no  consideration 
there  is  no  objection  to  building  as 
high  as  one  pleases;  but  for  the 
purely  utilitarian  purpose  of  steam 
making  equally  good  results  might       ; 
be  attained  with  a  shorter  chimney 
at  much  less  cost. 

The  intensity  of  draft  required  va- 
ries with  the  kind  and  condition  of 
the  fuel,  and  the  thickness  of  the 
fires.  Wood  requires  the  least,  and  ■ 
fine  coal  or  slack  the  most.  To 
burn  anthracite  slack  to  advantage, 


-^ 


°r 


a  draft  of  i^  inch  of  water  is  nec- 
essary, which  can  be  attained  by  a  well- 
proportioned  chimney  175  feet  high. 

Generally  a  much  less  height  than 
100  feet  cannot  be  recommended  for  a 
boiler,  as  the  lower  grades  of  fuel  can- 
not be  burned  as  they  should  be  with 
a  shorter  chimney. 

A  round  chimney  is  better  than 
square,  and  a  straight  flue  better  than  a 
tapering,  though  it  may  be  either  larger 
or  smaller  at  the  top  without  detriment. 

The  effective  area  of  a  chimney  for 
a  given  power  varies  inversely  as  the 
square  root  of  the  height.  The  actual 
area,  in  practice,  should  be  greater, 
because  of  retardation  of  velocity  due 
to  friction  against  the  walls.  On  the 
basis  that  this  is  equal  to  a  layer  of  air 
two  inches  thick  over  the  whole  inte- 
rior surface,  and  that  a  commercial 
horse-power  requires  the  consumption 
on  an  average  of  5  pounds  of  coal  per 
hour,  we  have  the  following  formulas: — 

0.3  H  ,_ 

E  =  -4=-  =  A  — 0.6  i/A  .     .     .     I 

V  h 

H=3.33  E  V~h 2 

S  =  12  1/  E  +  4 3 

D=  13.54  t/'E  +  4 4 

,         ,o.x  H? 

^'={-^) 5 

in  which  H  =  horse-power;  /z  =  height 
of  chimney  in  feet;  E  =  effective  area, 
and  A  =  actual  area  in  square  feet ;  S  ^ 
side  of  square  chimney,  and  D  =^  dia. 
of  round  chimney  in  inches.  The  table 
on  page  71  is  calculated  by  means  of 
these  formulas. 

To  find  the  draft  of  a  given  chimney 
in  inches  of  water:  Divide  j.6  by  the 
absolute  temperature  of  the  external 
air  (t^'^^  t  +  460);  divide  y.g  by  the 
absolute  temperature  of  the  gases  in 
the  chinmey  (t^  ^t'^  460);  subtract 
the  latter  from  the  former,  and  multi- 
ply the  remainder  by  the  height  of 
the  chim,ney  in  feet.  This  rule,  ex- 
pressed in  a  formula,  would  be: — 


To  find  the  height  of  a  chimney,  to 
give  a  specific  draft  power,  express- 
:'T-4 5,^?^*^^??'  ^^  in  inches  of  water:  Proceed  as 
.°,'„'.  ■'  \  .'j^y'-^  '   above,  through  the  first  two  steps, 
^i:.'i      then  divide  the  given  draft  power 


^ 


67 


4--< 


^ 


4"^ 


^ 


by  the  reinainder,  the  result  is  the  height  in  feet. 
Or,  by  formula  :  — 

d 


h 


7.6        7.9 


To  find  the  maximum  efficient  draft  for  any 
given  chimney,  the  heated  column  being  600  F., 


1           1           ' 

■ 

^<^ 

|:w£R£D~~ 

rz-- 

— = 

^-'•o? 

-MaJ=!^ 

^I 

— ^v^ 1 

\ 

h=iT-vJ-^ 

.■jcVAt- 

/ 

/ 

9f.^'. — 

/ 

——^ 

^^■^ 

and  the  external  air  62°  :  MiUtiply  the 
height  above  grate  iji  feet  by  .ooy, 
and  the  proditct  is  the  draft  power  hi 
inches  of  water. 

The  above  diagram  shows  the  draft,  in 
inches,  of  water  for  a  chimney  100  feet 
high,  under  different  temperatures,  from 
50°  to  800°  above  external  atmosphere, 
which  is  assumed  at  60°.  The  vertical 
scale  is  full  size,  and  each  division  is  -^-^ 
of  an  inch.  It  also  shows  the  relative 
quantity,  in  pounds  of  air,  which  would 
be  delivered,  in  the  same  time,  by  a 
chimney  under  the  same   differences  of 


temperature.  It  will  be  seen  that  practically 
nothing  can  be  gained  by  carrying  the  temper- 
ature of  the  chimney  more  than  350°  above  the 
external  air  at  60°. 

To  determine  the  quantity  of  air,  in  pounds, 
a  given  chimney  will  deliver  per  hour,  multiply 
the  distance  in  inches,  at  given  temperature,  on 

the  diagram, 
by  1000  times 
the  effective 
area  in  square 
feet,  and  by 
the  square  root 
of  the  height 
in  feet.  This 
gives  a  maxi- 
ctK)      ouo      7UU      750      800  mum.        Fric- 

tion   in    flues 
and  furnace  may  reduce  it  greatly. 

The  external  diameter  of  a  brick  chim- 
ney at  the  base  should  be  one-tenth  the 
height,  unless  it  be  supported  by  some 
other  structure.  The  "batter"  or  taper 
of  a  chimney  should  be  from  jV  to  X  inch 
to  the  foot  on  each  side. 

Thickness  of  brick  work  :  one  brick  (8 
or  9  inches )  for  25  ft.  from  the  top,  increas- 
ing Yz  brick  (4  or  4>^  inches)  for  each  25 
ft.  from  the  top  downwards. 

If  the  inside  diameter  exceed  5  ft.  the 
top  length  should  be  ij^  bricks,  and  if 
under  3  ft.  it  may  be  Yz  brick  for  ten  feet. 


Chimney  for  1260  H.P.  of  Babcock  &  Wilcox  Boiler,  at  Bird  Coleman  Furnace,  Cornwall,  Pa. 


^ 


-►^ 


SIZES  OF  CHIMNEYS  WITH  APPROPRIATE  HORSE-POWER  OF  BOILERS. 


Diameter 

Height  of  C 

HIMNEY.S 

AND  Commercial  Horse-Power. 

Side  of 

Effective 

Actual 
Area. 

in 

Square 
Feet. 

Square 
Feet. 

Inches,    -q 

ft. 

60  ft.  - 

0  ft.  8c 

ft. 

90  ft. 

100  ft.  1 

10  ft. 

125  ft. 

i5oft.ji75ft. 

200  ft.    I"ches. 

l8               2 

3 

25 

27 

16 

0.97 

1-77 

21               3 

■^ 

38 

41 

19 

1-47 

i.41 

24           4 

9 

54 

S8 

62 

22 

2.08 

3-14 

27           6 

5 

72 

78 

«3 

24 

2.78 

3-98 

3°           8 

4 

92 

100      I 

07 

"3 

27 

3.58 

4.91 

33 

"5 

125      I 

33 

141 

30 

4.48 

5-94 

36 

Ml 

152      I 

63 

'73 

182 

32 

5-47 

7-07 

39 

183      I 

g6 

208 

219 

35 

6.57 

8.30 

42 

216      2 

31 

24^ 

258 

271 

38 

7.76 

9,62 

48 

•••       3 

11 

330 

348 

365 

389 

43 

10.44 

12.57 

54 

•••       3 

63 

427 

449 

472 

503 

551 

48 

13-51 

15.90 

60 

...       5 

OS 

53b 

565 

593 

632 

692 

748 

54 

16.98 

19.64 

66 

bs8 

694 

728 

776 

849 

918 

98 

59 

20.83 

23-76 

72 

792 

835 

876 

934 

1023 

1 105 

118 

64 

25.0S 

28.27 

78 

995      1 

038 

1 107 

1212 

1310 

1 40c 

>            70 

29-73 

33-18 

84 

1163      1 

214 

1294 

1418 

1531 

1637   1         75 

34-76 

38-48 

go 

1344      ' 

415 

1496 

1639 

1770 

189 

80 

40.19 

44.18 

96 

1537      I 

616 

1720 

1876 

2027 

2lb 

7           86 

46.01 

50-27 

102 

1946 

2133 

2303 

246^ 

90 

52.23 

56.75 

108 

2192 

2402 

2594 

277. 

96 

58-83 

63.62 

114 

2459 

2687 

2903 

300, 

lOI 

65-83 

70.88 

120 

2990 

3230 

3452   1        106 

73.22 

78-54 

126 

3308 

3573 

382c 

3          112 

81.00 

86.59 

132 

3642 

3935 

420 

)           "7 

89.19 

95-03 

138 

3991 

43" 

460 

5           122 

97-75 

103.86 

144 

435- 

4707 

503 

127 

106.72 

1:3.10 

i  14  8  inn  .If-illn* 


/RON  CHIMNEY  STACKS. 

In    many    places    iron    stacks 

are  preferred  to  brick  chimneys. 

The  cuts  on  the   margin  of  this 

page    show   the    stacks    of    the 

Maryland  Steel  Co.,  at  Sparrow's 

Point,  Md.     These  are  lined  with 

brick  their  whole  height  and  are 

bolted  down  to  the  base  so  as  to 

require  no  stays.    A  good  method 

of  securing  such  bolts  to  the  stack 

is  practiced  by  the  Pencoyd  Iron 

Works,    Pa.,    and    is    shown    in 

detail    in    the    annexed    figures. 

Iron  stacks  require  to  be   kept 

well  painted  to  prevent  rust,  and 

generally,  where  not  bolted  down, 

as  here  shown,  they  need  to  be 

braced  by  rods  or  wires  to  sur- 
rounding objects.    With  four  such 

braces  attached  to  an  angle 

iron  ring  at  %  the  height 

of    stack,     and     spreading 

laterally  at  least  an  equal 

distance,  each  brace  should 

have  an  area  in  square  inches  equal  to  i-iooo 
I  the    exposed    area    of 

stack  (dia.   X  height) 
in  feet. 

Stability,  or  power 
to  withstand  the  over- 
turning force  of  the 
highest  winds,  requires 
a  proportionate  re- 
lation     between      the 


C 


TV, 


F 


Holding  Down  Bolts  and 

Lugs, 

Pencoyd  Iron  Works. 


weight,  height,  breadth  of 
base,  and  exposed  area  of 
the  chimney.  This  relation 
is  expressed  in  the  equation 

b 
in  which  d  =  the  average 
breadth  of  the  shaft ;  h  =  its 
height ;  d  =  the  breadth  of 
base, — all  in  feet ;  IV 
=  weight  of  chimney 
in  lbs. ,  and  C^  a  co- 
efficient of  wind  pres- 
sure per  square  foot 
of  area.  This  varies 
with  the  cross-sec- 
tion of  the  chimney, 
and  =  56  for  a 
square,  35  for  an  oc- 
tagon, and  28  for 
a  round  chimney. 
Thus  a  square  chimney  of 
average  breadth  of  8  feet,  10 
feet  wide  at  base  and  100 
feet  high,  would  require  to 
weigh  56  X  8  X  100  X  10  = 
448,000  lbs.  to  withstand  any 
gale  likely  to  be  experienced. 
Brickwork  weighs  from  100 
to  130  lbs.  per  cubic  foot, 
hence  such  a  chimney  must 
average  13  inches  thick 
to  be  safe.  A  round 
stack  could  weigh  half  as 
much,  or  have  less  base. 


^ 


iDii 


fl==^-- 


>■-♦■ 


71 


^-f 


ijii 

13  ii 
11  i-' 
III! 

IIW 

'•"'■*  Si  1! 


5-  *'  !!sl!!5S| 

iii'i 


ti 


■%w 


iSlilllliiHiliJSiii 

Ii  iiiJJlMlMliiiiTfi- 
ffftiriririK. 

iifiir 


Land  Title  &  Trust  Co.  Building,  Philadelphia,  Pa.     350  H.P.  Babcock  &  Wilcox  Boaers 


•i^ 


— * 


PROPERTIES  OF  SATURATED  STEAM. 

Ice  is  liquified  and  becomes  water  at  32°  F. 
Above  this  point  water  increases  in  temperature 
up  to  the  steaming  point,  nearly  at  the  rate  of  1° 
for  each  unit  of  heat  added  per  pound  of  water. 
The  steaming  point  (212°  at  atmospheric  pres- 
sure) rises  as  the  superimposed  pressure  in- 
creases, but  at  a  decreasing  ratio;  as,  for  ex- 
ample, at  atmospheric  pressure  it  takes  y/i°  to 
add  a  pound,  while  at  150  pounds  %°  gives  the 
same  increase  of  pressure. 

For  each  unit  of  heat  added  above  the  steam- 
ing point,  a  portion  of  the  water  is  converted  into 
steam, having  the  same  temperature  and  the  same 
pressure  as  that  at  which  it  is  evaporated.  The 
heat  so  absorbed  is  called  ' '  Latent  Heat. ' '  The 
amount  of  heat  rendered  latent  by  each  pound  of 
water  in  becoming  steam  varies  at  different  pres- 
sures, decreasing  as  the  pressure  increases.  This 
latent  heat  added  to  the  sensible  heat  (or  the 


thermometric  temperature)  constitutes  the 
"Total  Heat."  The  "total  heat"  being  greater 
as  the  pressure  increases,  it  will  take  more  heat, 
and  consequently  more  fuel,  to  make  a  pound  of 
steam  the  higher  the  pressure. 

Saturated  steam  cannot  be  cooled  except  by 
lowering  its  pressure,  the  abstraction  of  heat  be- 
ing compensated  by  the  latent  heat  of  a  portion 
which  is  condensed.  Neither  can  steam,  in 
contact  with  water,  be  heated  above  the  tem- 
perature normal  to  its  pressure. 

The  density  of  saturated  steam  varies  from  ^ 
that  of  air  of  the  same  temperature  and  pressure, 
below  that  of  the  atmosphere,  to  %  at  100  pounds. 
Its  weight  per  cubic  foot  varies  as  the  17th  root 
of  the  1 6th  power,  and  may  be  found  by  the 
formula  :  D  =  .003027/"  ■^*^,  which  is  correct  to 
within  \  per  cent,  up  to  250  pounds  pressure. 

The  following  table  gives  the  properties  of 
steam  at  different  pressures  — ■  from  i  lb.  to  500. 


TABLE  OF   PROPERTIES   OF  SATURATED   STEAM,   Partly  from  C.  H.  Peabody's  Tables. 


Pressure  in 

Heat  of 

pounds  per 

square  inch 

above 

Tertiperature 
in  degrees, 
Fahrenheit. 

Total  heat 
in  heat  units 

Heat 
in  liquid 

vaporization, 
or  latent 

Density 
or  weight 

Volume      F 
of  one  pound  of  ec 

actor 
[uivalent 

Total 
pressure 

from  water 

from  32°  in 

heat  in  heat 

of  cubic  foot 

in  cubic    eva] 

ioration 

above 

vacuum. 

at  32°. 

units. 

units. 

in  pounds. 

feet.       at 

212°. 

vacuum. 

I 

101.99 

1113.1 

70.0 

1043.0 

0.00299 

334-5 

9661 

I 

2 

126 

27 

1120 

5 

94 

4 

1026 

I 

0.00576 

173 

6 

9738 

2 

3 

141 

62 

1125 

I 

109 

8 

1015 

3 

0.00844 

118 

5 

9786 

3 

4 

153 

09 

1 128 

6 

121 

4 

1007 

2 

0.01107 

90 

33 

9822 

4 

5 

162 

34 

1131 

5 

130 

7 

1000 

8 

0.01366 

73 

21 

9852 

5 

6 

170 

14 

1133 

8 

138 

6 

995 

2 

0.01622 

61 

65 

9876 

6 

7 

176 

90 

"35 

9 

145 

4 

990 

5 

0.01874 

53 

39 

9897 

7 

8 

182 

92 

"37 

7 

151 

5 

986 

2 

0.02125 

47 

06 

9916 

8 

9 

188 

33 

"39 

4 

156 

9 

982 

5 

0.02374 

42 

12 

9934 

9 

ID 

193 

25 

I  HP 

9 

161 

9 

979 

0 

0.02621 

38 

15 

9949 

10 

15 

213 

03 

1 146 

9 

181 

8 

965 

I 

0.03S26 

26 

14         I 

0003 

IS 

20 

227 

95 

1151 

5 

196 

9 

954 

6 

0.05023 

19 

91         I 

0051 

20 

25 

240 

04 

"55 

I 

209 

I 

946 

0 

0.06199 

16 

13         I 

0099 

25 

30 

250 

27 

"58 

3 

219 

4 

938 

9 

0.07360 

13 

59         I 

0129 

30 

35 

259 

19 

1161 

0 

228 

4 

932 

6 

0.0850S 

II 

75         I 

0157 

35 

40 

267 

13 

1 163 

4 

236 

4 

927 

0 

0.09644 

10 

37         I 

0182 

40 

45 

274 

29 

1 165 

6 

243 

6 

922 

0 

0.1077 

9 

285 

0205 

45 

5° 

280 

85 

1 167 

6 

250 

2 

917 

4 

0.1 188 

8 

418 

0225 

50 

55 

286 

89 

1 169 

4 

256 

3 

913 

I 

0.1299 

7 

698        I 

0245 

55 

60 

292 

SI 

1171 

2 

261 

9 

909 

3 

0.1409 

7 

097        I 

0263 

60 

65 

297 

77 

1172 

7 

267 

2 

905 

5 

0.1519 

6 

583 

0280 

65 

70 

302 

71 

"74 

3 

272 

2 

go2 

I 

0.1628 

6 

143        I 

0295 

70 

75 

307 

38  ~ 

"75 

7 

276 

9 

898 

8 

0.1736 

5 

760        I 

0309 

75 

80 

311 

80 

"77 

0 

281 

4 

895 

6 

0.1843 

5 

426        I 

0323 

80 

85 

316 

02 

1 178 

3 

285 

8 

892 

5 

0.1951 

5 

126        I 

0337 

85 

go 

320 

04 

"79 

6 

290 

0 

889 

6 

0.2058 

4 

859 

0350 

90 

95 

323 

89 

1 180 

7 

294 

0 

886 

7 

0.2165 

4 

6ig       I 

0362 

95 

100 

327 

58 

1181 

9 

297 

9 

884 

0 

0.2271 

4 

403       I 

0374 

100 

105 

331 

13 

1 182 

9 

301 

6 

881 

3 

0.2378 

4 

205       I 

0385 

IDS 

no 

334 

56 

1 184 

0 

305 

2 

878 

8 

0.2484 

4 

026       I 

0396 

no 

"5 

337 

86 

"85 

0 

-  308 

7 

876 

3 

0.2589 

3 

862       I 

0406 

"5 

120 

341 

05 

1186 

0 

312 

0 

874 

0 

0.2695 

3 

711       I 

0416 

120 

125 

344 

13 

1 186 

9 

315 

2 

871 

7 

0.2800 

3 

571       I 

0426 

I2S 

130 

347 

12 

1187 

8 

318 

4 

869 

4 

0.2904 

3 

444        I 

0435 

130 

140 

352 

85 

1 189 

5 

324 

4 

865 

I 

o.3"3 

3 

212        I 

0453 

140 

150 

358 

26 

1191 

2 

330 

0 

861 

2 

0.3321 

3 

on        I 

0470 

150 

i6o 

363 

40 

1 192 

8 

335 

4 

857 

4 

0.3530 

2 

833 

0486 

160 

170 

368 

29 

"94 

3 

340 

5 

853 

8 

0.3737 

2 

676        I 

0502 

170 

180 

372 

97 

"95 

7 

345 

4 

850 

3 

0-3945 

2 

535        I 

0517 

180 

190 

377 

44 

"97 

I 

350 

I 

■847 

0 

0.4153 

2 

408        I 

0531 

igo 

200 

381 

73 

1 198 

4 

354 

6 

843 

8 

0.4359 

2 

294        I 

0545 

200 

225 

391 

79 

1201 

4 

365 

I 

836 

3 

0.4S76 

2 

051        I 

0576 

225 

250 

400 

99 

1204 

2 

374 

7 

829 

5 

0.5393 

854 

0605 

250 

275 

409 

50 

1206 

8 

383 

6 

823 

2 

0.5913 

6gi       I 

0632 

275 

300 

417 

42 

1209 

3 

391 

9 

817 

4 

0.644 

553       I 

0657 

300 

32s 

424 

82 

1211 

5 

399 

6 

811 

9 

0.696 

437        I 

0680 

325 

350 

431 

90 

1213 

7 

406 

9 

806 

8 

0.748 

337        I 

0703 

350 

375 

438 

40 

1215 

7 

414 

2 

801 

5 

0.800 

250        I 

0724 

37S 

400 

445 

15 

1217 

7 

421 

4 

796 

3 

0.853 

172        I 

0745 

400 

500 

466 

57 

1224 

2 

444 

3 

779 

9 

1.065 

939        I 

0812 

500 

►it 


73 


■HH 


i    >    1  J  ~  '^^ 


Empire  Building,  Hew  York.      911  H.P.  Babcock  &  Wilcox  Boilers. 


The  gauge  pressure  is  about  15  pounds 
(14.7)  less  than  the  total  pressure,  so  that 
in  using  this  table,  15  must  be  added  to  the 
pressure  as  given  by  the  steam  gauge.  The 
column  of  Temperatures  gives  the  thermo- 
metric  temperature  of  steam  and  the  boiling 
point  at  each  pressure.  The  "factor  of  equiv- 
alent evaporation"  shows  the  proportionate 
cost  in  heat  or  fuel  of  producing  steam  at  the 
given  pressure  as  compared  with  atmospheric 
pressure. 

To  ascertain  the  equivalent  evaporation  at 
any  pressure,  multiply  the  given  evaporation  by 


the  factor  of  its  pressure,  and  divide  the  product 
by  the  factor  of  the  desired  pressure. 

Each  degree  of  difference  in  temperature  of 
feed-water  makes  a  difference  of  .00104  in  the 
amount  of  evaporation.  Hence,  to  ascertain 
the  equivalent  evaporation  from  any  other  tem- 
perature of  feed  than  212°,  add  to  the  factor 
given  as  many  times  .00104  ^s  the  temperature 
of  feed-water  is  degrees  below  212°.  For  other 
pressures  than  those  given  in  the  table,  it  will 
be  practically  correct  to  take  the  proportion  of 
the  difference  between  the  nearest  pressures 
given  in  the  table. 


FACTORS   OF   EVAPORATION. 
From  the  Tables  computed  by  Mr.  Geo.  A.  Rowell. 


v|lS 

Steam  Pressure  by  Gauge. 

50      60 

1.214  1. 216 

70 

80 

90 

IC30 

no 

120 

130 

140 

150 

160 

170 

180 

igo 

200 

210 

220 

230 

240 

250 

260 

270 

280 

2go 

300 

32 

1.220 

1.222 

1.225 

1.227 

1.229 

r.231 

1.232 

1.234 

1.236 

1-237 

1.239 

1.240 

1.241 

1-243 

1.244 

1.245 

1.246 

1.247 

1.248 

1.250 

1-251 

r.252 

i-z.SS 

1.254 

40 

1.206 1.209 

1. 212 

i.2r4 

1.216 

I.2I9 

1.220 

1.222 

1.224 

1.226 

1.227 

i.22g 

1.230 

1.232 

1-233 

1-234 

1.236 

'-237 

1.238 

1-239 

1.240 

1.241 

1.242 

1-243 

1.244 

1.245 

.so 

'•'§5'-i97 

1.201 

1.204 

r.2o6 

1.208 

I.2IO 

1. 212 

I.214 

1.215 

1.217 

1. 218 

1.220 

1. 221 

1.223 

1.224 

1.225 

1.226 

1.22S 

1.229 

1.230 

1.231 

1.232 

1-233 

1-234 

1-235 

60 

i.iSs'i.iSS 

1. 191 

i-iq3 

1.196 

1. 198 

1.200 

1.202 

1.203 

1.205 

1.207 

1.208 

1. 210 

1.211 

1. 212 

1.214 

1.21S 

1.216 

1. 217 

t.2l8 

1.219 

1.220 

1.221 

1.222 

1.223 

1.224 

70 

1.1751.178 

i.iSo 

1.1S3 

i.iSs 

1. 187 

1. 189 

1. 191 

I-I93 

1-194 

i.igb 

1. 197 

1. 199 

1.200 

1.202 

1.203 

r.2os 

1.206 

1.207 

1.208 

1.209 

1.210 

1.211 

1. 212 

1.213 

1.214 

80 

1. 164  1. 167 

1. 170 

1. 173 

1.17s 

1. 177 

1.179 

1. 181 

I-I83 

1. 184 

i.i8b 

1. 187 

1. 189 

1. 190 

1.192 

1. 193 

1. 194 

1.19s 

i.igb 

i.ig8 

i.igq 

1.200 

1.201 

1.202 

1.203 

1.204 

qo 

1.1541.157 

1. 160 

1. 162 

1. 165 

1. 167 

i.i6g 

1. 170 

1.172 

1. 174 

1. 176 

1.177 

i.i/g 

1. 180 

1. 181 

1. 183 

1. 184 

i.i8s 

i.i8b 

1. 187 

1. 188 

1.189 

1. 190 

1. 191 

1. 192 

I -193 

100 

1.1441-147 

1. 150 

I.IS2 

I.IS4 

1. 156 

1.158 

1. 160 

1. 162 

1. 164 

I. lbs 

1. 167 

1. 168 

[.170 

1. 171 

1.172 

1. 174 

1.17s 

1.17b 

1. 177 

1. 178 

1.179 

1. 180 

1. 181 

1. 182 

1.183 

no 

I-I33I-I36 

i-i3q 

1. 142 

1. 144 

1. 146 

1. 148 

1.150 

1.152 

I-IS3 

I.ISS 

1. 156 

I.I  58 

I.IS9 

1. 160 

1. 162 

1.163 

1.164 

i.ibb 

1.167 

I.I68 

1. 169 

1. 170 

1. 171 

1. 172 

1-173 

120 

1.1231.126 

1. 129 

1. 131 

I-I33 

1.136 

i.i3« 

1. 140 

1. 141 

I-I43 

'-I45 

1.146 

1. 147 

1. 149 

1. 150 

1. 151 

1-153 

1-154 

i-i-SS 

1.156 

1-157 

1.158 

I.I.S9 

1. 160 

1. 161 

1. 162 

130 

I.ii3'i.ii6 

i.iiS 

1. 121 

1. 123 

1. 125 

1. 127 

1. 129 

1. 130 

1. 132 

•-I34 

1. 136 

I-137 

1. 138  1. 140 

1. 141 

1.142 

1. 144 

1-14.S 

1. 146 

1. 147 

1.148 

1. 149 

1. 150 

1-151 

1. 152 

140 

1.1021.105 

i.ioS 

I. no 

I.I  13 

I.II5 

1. 117 

1. 119 

1. 120 

1. 122 

1. 124 

1. 125 

1. 127 

1. 128 

1. 129 

1. 131 

1.132 

1-133 

1-134 

I-I3S 

1. 136 

I-137 

1. 138 

1-139 

1. 140 

1.141 

ISO 

1.0911.095 

r.ogS 

1. 100 

1. 102 

1. 104 

1. 106 

1. 108 

I. no 

I. Ill 

1.113 

i.nS 

I. lib 

1. 118 

1. 119 

1. 120 

1. 121 

1. 123 

1. 124 

1. 125 

1.126 

1. 127 

1.128 

1. 129 

1. 130 

1.131 

160 

i.oSi|i.oS4 

1.087 

1.090 

1.092 

1.094 

1.096 

1.098 

I. TOO 

I.IOI 

1. 103 

1. 104 

i.iob 

1. 107 

1. 108 

I. no 

I. in 

1. 112 

I.I  13 

I.IIS 

1. 116 

1. 117 

i.n8 

1. 119 

1. 120 

1. 121 

170 

1.070  1.074 

1.077 

1.079 

i.oSi 

1.083 

1.08  s 

I.0S7 

1.089 

1. 09 1 

1.092 

1.094 

1. 09  5 

1.097 

1.098 

1-099 

I.IOI 

1. 102 

1. 103 

1. 104 

1. 105 

1. 106 

1. 107 

1. 108 

i.iog 

I. no 

I  So 

1 .060  1 .063 

i.obb 

1.069 

1. 07 1 

1-073 

1.07  s 

1.077 

1.079 

1.080 

1.082 

1.083 

1.08s 

1. 08b 

1.08S 

1.089 

i.ogo 

1. 09 1 

i.og3 

i.og4 

1. 09  5 

1.096 

1.097 

1.09S 

i.ogg'i.ioo 

I  go 

1.050  1.053 

1.056 

i.osS 

1.060 

1.063 

1.06  s 

1.066 

1.068 

1.070 

1. 07 1 

1.073 

1.074 

1.076  1.077 

1.07811.080 
1.068  1.069 

i.oSi 

1.082 

1083 

1.084 

1.085 

1.086 

1.087 

1.088^1.089 

200 

1.039  1.043 

1.04  s 

1.04S 

i.oso 

1.052 

I.OS4 

1.056 

1.0S8 

i.osg 

1. 06 1 

1. 063  1. 064 

1.065  1.067 

1. 07 1 

1.072 

1-073 

1.074 

1.07  s 

1.076 

1.077 

i.078|i.079 

210 

1.029  1.032  1.035 

I -03  7 

1.040 

1.042 

1.044 

1.046 

1.047 

1.049 

1.05 1 

1.052  1.053 

1.0551.056 

1.0571.059 

1.060 

1. 06 1 

1.062 

1.063 

1.064 

1. 065 

1.066 

1.067,1.068 

WATER  AT  DIFFERENT  TEMPERATURES. 

There  are  four  notable  temperatures  for  pure 
water,  viz. :  — ■ 

1.  Freezing  point  at  sea  level,      ....  32°  F. 

2.  Point  of  maximum  density,      ....  39.1°  F. 

3.  British  standard  for  specific  gravity,      .  62°  F. 

4.  Boiling  point  at  sea  level, 212°  F. 

32°      F.  Weight  per  cub.  ft.,  62.418  lb.;  per  cub.  in.,  .03612  lb. 

39.1°  F.  Weight  per  cub.  ft.,  62.425  lb.;  per  cub.  in.,  .0361251b. 

62°      F.  Weight  per  cub.  ft.,  62.355  lb.;  per  cub.  in.,  .03608  lb. 

212°    F.  Weight  per  cub.  ft.,  5g.76o  lb.;  per  cub.  in.,  .03458  lb. 

A  United  States  Standard  gallon  holds  231 
cubic  inches  and  Sy^  lbs.  of  water  at  62°  F. 

A  British  Imperial  gallon  holds  277.274  cubic 
inches  and  10  lbs.  of  water  at  62°  F. 

Sea  water  (average)  has  a  specific  gravity  of 
1.028,  boils  at  213.2°  F.,  and  weighs  64  lbs.  per 
cubic  foot  at  62°  F. 

A  pressure  of  i  lb.  per  sq.  in.  is  exerted  by  a  col- 
umn of  water  2. 3093  ft.,  or  27.71  in.  high,  at  62°  F. 

In  solvent  power  water  has  a  greater  range 
than  any  other  liquid.  For  common  salt  this  is 
nearly  constant  at  all  temperatures,  while  it  in- 
creases with  increase  of  temperature  for  others, 


magnesium  and  sodium  sulphates,  for  instance. 
Where  water  contains  carbonic  acid  it  dissolves 
some  minerals  quite  readily,  but  a  boiling  tem- 
perature causes  the  disengagement  of  the  car- 
bonic acid  in  gaseous  form  and  the  deposition  of 
a  large  part  of  the  minerals  thus  held  in  solution. 
Lime  salts  are  more  soluble  in  cold  than  in  hot 
water,  and  most  of  them  are  deposited  at  320°, 
or  less.  When  frozen  into  ice,  or  evaporated 
into  steam,  water  parts  with  nearly  all  substances 
held  in  solution. 

TABLE  OF  SOLUBILITIES  OF  SCALE-MAKING  MINERALS. 


Soluble 

in  parts 

Soluble 

in  parts 

in  parts 

Insolu- 

Substance. 

of  pure 

of  pure 

ble  iu 

water 

water 

water  at 

at32°F. 

cold. 

at  212°. 

Carbonate  of  Lime,     .     . 

62,500 

150 

62,500 

302°  F. 

Sulphate  of  Lime,  .     .     . 

500 

460 

302°  F. 

Carbonate  of  Magnesia,  . 

5,500 

150 

9,600 

Phosphate  of  Lime,     .     . 

1,333 

212°  JF. 

Oxide  of  Iron,    .... 

212°  F. 

Silica, 

Und't'd 

212°  F. 

Water  has  a  greater   specific   heat,  or  heat- 
absorbing  capacity,  than  any  other  known  sub- 


►i:^ 


^ 


stance  (bromine  and  hydrogen  excepted),  and  is 
the  unit  of  comparison  employed  for  all  meas- 
urements of  the  capacities  for  heat  of  all  sub- 
stances whatever.  The  specific  heat  of  water  is 
not  constant,  but  rises  in  an  increasing  ratio  with 
the  temperature,  so  that  it  requires  slightly  more 
heat,  the  higher  the  temperature,  to  raise  a  given 
quantity  of  water  from  one  temperature  to 
another.  The  specific  heat  of  ice  and  steam  are, 
respectively,  .504  and  .475,  or  practically  about 
half  that  of  water. 


A  British  Thermal  Unit  (or  heat  unit)  is  that 
quantity  of  heat  which  will  raise  one  pound  of 
water  at  or  about  freezing  point,  1°  F.  A 
French  "  Calorie  "  is  the  heat  required  to  raise 
one  kilogramme  of  water  1°  C,  and  is  equal  to 
3.96S32  British  thermal  units. 

The  following  table  gives  the  number  of  British 
thermal  units  in  a  pound  of  water  at  different  tem- 
peratures. They  are  reckoned  above  32°  F., 
for,  strictly  speaking,  luater  does  not  exist  below 
32°,  and  ice  follows  another  law. 


WATER   BETWEEN   32°  AND   212°  F. 


Temper- 

Heat 

Weight, 

Temper- 

Heat 

Weight, 

Temper- 

Heat 

Weight, 

Temper- 

Heat 

Weight, 

ature 

Units 

lbs.  per 

ature 

Units 

lbs .  per 

ature 

Units 

lbs.  per 

ature 

Units 

lbs.  per 

Fahr. 

per  lb. 

cubic  foot. 

Fahr. 

per  lb. 

cubic  foot. 

Fahr. 

per  lb. 

cubic  foot. 

Fahr. 

per  lb. 

cubic  foot. 

■32° 

0.00 

62.42 

no'-' 

78.00 

61.89 

145° 

113.26 

61.28 

179° 

147-54 

60.57 

35 

3.02 

62.42 

112 

80.00 

61.86 

146 

114.27 

61.26 

180 

148.54 

60.55 

40 

8.06 

62.42 

113 

81.01 

61.84 

147 

115.28 

61.24 

181 

149.55 

60.53 

45 

13.08 

62.42 

114 

82.02 

61.83 

148 

116.29 

61.22 

1 82 

150.56 

60.50 

5° 

18.10 

62.41 

115 

83.02 

61.82 

149 

117.30 

61.20 

183 

151.57 

60.48 

52 

20.11 

62.40 

116 

84.03 

61.80 

150 

118.30 

61.18 

184 

152.58 

60.46 

54 

22.11 

62.40 

117 

85.04 

61.78 

151 

119. 31 

61.16 

185 

153-58 

60.44 

56 

24.11 

62,39 

118 

86.05 

61.77 

152 

120.32 

61.14 

186 

154-59 

60.41 

58 

26.12 

62.38 

119 

87.06 

61-75 

153 

121.33 

61.12 

187 

155.60 

6o.3g 

60 

28.12 

62.37 

120 

88.06 

61,74 

154 

122.34 

61.10 

188 

156.61 

60,37 

62 

30.12 

62.36 

121 

89.07 

61.72 

155 

123-34 

61.08 

i8g 

157,62 

60.34 

64 

32.12 

62.35 

122 

90.08 

61.70 

156 

124-35 

61.06 

I  go 

158,62 

60.32 

66 

34.12 

62.34 

123 

91.09 

61,68 

157 

125.36 

61.04 

igi 

159-63 

60.29 

68 

36.12 

62.33 

124 

92.10 

61.67 

158 

126.37 

61.02 

192 

160,63 

60.27 

70 

38.11 

62.31 

125 

93.10 

61.65 

159 

127.38 

61.00 

193 

161.64 

60.25 

72 

40.11 

62.30 

126 

94.11 

61,63 

160 

128.3S 

60.98 

194 

162.65 

60.22 

74 

42.11 

62.28 

127 

95.12 

61.61 

161 

129.39 

60.96 

195 

163.66 

60.20 

76 

44- n 

62.27 

128 

96.13 

61.60 

162 

130.40 

60.94 

196 

164.66 

60.17 

78 

46.10 

62.25 

129 

97-14 

61.58 

163 

131. 41 

60.92 

197 

165.07 

60.15 

80 

48.09 

62.23 

130 

98.14 

61.56 

164 

132.42 

60.  go 

ici8 

166.68 

60.12 

82 

50.08 

62.21 

131 

99-15 

61.54 

.65 

133.42 

60.87 

199 

167.69 

60.  lO 

84 

52.07 

62.19 

132 

100. 16 

61.52 

166 

134.43 

60.85 

200 

168.70 

60.07 

86 

54.06 

62.17 

133 

101.17 

61.51 

167 

135.44 

60.83 

201 

169.70 

60.05 

88 

56.05 

62.15 

134 

102.18 

61.49 

168 

136.45 

60.81 

202 

170.71 

60.02 

go 

58.04 

62.13 

135 

103.18 

61.47 

i6g 

137-46 

60.79 

203 

171.72 

60.00 

92 

60.03 

62.11 

136 

104.19 

6..45 

170 

138.46 

60.77 

204 

172.73 

59.97 

94 

62.02 

62.09 

137 

105.20 

61,43 

171 

139.47 

60.75 

205 

173.74 

59-95 

96 

64,01 

62.07 

138 

106.21 

61,41 

172 

140.48 

60.73 

206 

174.74 

59.92 

98 

66.01 

62.05 

139 

107.22 

61.39 

173 

141.49 

60.70 

207 

175.75 

59. 8g 

100 

68.01 

62.02 

140 

108.22 

61.37 

174 

142.50 

60.68 

208 

176.76 

59.87 

102 

70.00 

62.00 

141 

109.23 

61,36 

175 

143.50 

60.66  , 

2og 

177.77 

59.84 

104 

72.00 

61.97 

142 

110.24 

61.34 

176 

144.51 

60.64 

210 

178.78 

59.82 

106 

74.00 

61.95 

143 

III. 25 

61.32 

177 

145.52 

60.62 

211 

179.78 

59.79 

108 

76.00 

61,92 

144 

112.26 

61.30 

178 

146.53 

60.59 

212 

i8o.7g 

59.76 

PRIMING  OR  WET  STEAM. 

A  fault,  frequently  met  with  in  steam  boilers,  is 
the  carrying  over  of  water  mechanically  mixed 
with  the  steam,  which  water  not  only  carries  away 
heat  without  any  useful  effect,  but,  when  present 
in  any  marked  quantity,  itself  becomes  a  source 
of  danger  and  of  serious  loss  in  the  engine.  This 
is  a  point  frequently  forgotten  in  designing  boil- 
ers, particularly  sectional  boilers.  If  steam  rises 
from  a  surface  of  water  faster  than  about  2  ft.  6 
in.  to  3  ft.  per  second,  it  carries  water  with  it  in 
the  form  of  spray,  and  when  a  fine  spray  is  once 
formed  in  steam  it  does  not  readily  settle  against 
a  rising  current  of  very  low  velocity,  as  a  current 
of  I  ft.  per  second  will  carry  with  it  a  globule  of 
water  ^^q-q  of  an  inch  in  diameter. 


Many  boilers  show  a  high  apparent  evapora- 
tion in  consequence  of  furnishing  "wet  steam," 
while  practically  they  are  anything  but  econom- 
ical. Parties  have  been  known  to  claim  an  evap- 
oration of  19  or  20  pounds  per  pound  of  coal, 
where  the  highest  practically  possible  is  not  over 
13.     Such  boilers  are  dear  at  any  price. 

The  cause  of  priming  may  be  either  impure 
water,  too  much  water,  or  improper  proportions 
in  the  boiler.  When  a  boiler  is  found  to  form 
wet  steam  with  good  water,  carried  at  a  proper 
height,  it  is  a  proof  of  wrong  design. 

The  amount  of  priming  in  different  boilers 
varies  greatly,  and  as  yet  there  is  not  sufficient 
data  to  establish  any  definite  ratio  for  boilers  in 
ordinary  use.     The  experiments  of  M.  Hirn,  at 


►  ■4- 


77 


4i 


Mulhouse,  showed  an  average  of  at  least  5  per 
cent.;  Zeuner  sets  it  down  as  approximately 
from  tYz  to  15  per  cent.;  the  careful  experiments 
at  the  American  Institute  in  1871  show  in  cylin- 
drical tubulars  7.9  per  cent.,  and  in  the  tests  at 
the  Centennial  Exposition  one  boiler  showed  as 
high  as  18.57  per  cent,  priming. 

In  sixteen  different  tests  of  the  dryness  of  the 
steam  from  Babcock  &  Wilcox  boilers  made  by 
ten  different  engineers,  the  average  moisture  in 
the  steam  was  only  0.82  per  cent.  The  highest 
was  4. 16  per  centt,  which  was  less  than  the  same 
engineer  with  the  same  apparatus  found  in  large 
two-flue  boilers,  working  very  lightly. 


tight  with  rubber  or  asbestos  gaskets,  which  also 
act  as  non-conductors  of  heat.  For  convenience 
a  union  is  placed  near  the  valve  as  shown,  and 
the  exhaust  steam  may  be  led  away  by  a  short 
\%  inch  pipe,  shown  by  dotted  lines.  The 
thermometer  wells  are  filled  with  mercury  or 
heavy  cylinder  oil,  and  the  whole  instrument 


This  is  wrong. 


TESTS  FOR  MOISTURE. 

In  boiler  trials  it  is  essential  to  know  the  qual- 
ity of  the  steam  generated:  whether  it  is  wet, 
dry,  or  superheated.  For  many  years  the  stand- 
ard apparatus  for  ascertaining  this  was  the  barrel 
calorimeter  (seep,  iii),  but  this  has,  of  late,  been 
superseded  by  the  throttling  calorimeter,  an  in- 
strument first  devised  by  Prof.  C.  H.  Peabody  of 
the  Massachusetts  Institute  of  Technology  (see 
Journal  of  Franklin  Institute,  August,  1888),  and 
which,  when  properly  handled,  and  connected, 
gives  results  far  more  accurate  than  can  be  ob- 
tained in  any  other  way. 

There  have  been  numerous  forms  of  this  in- 
strument, one  of  the  simplest  being  that  de- 
signed by  Mr.  George  H.  Barrus,  of  Boston, 
which  is  described  below:  — 

Steam  is  taken  from  a  %  inch  pipe  provided 
with  a  valve  and  passes  through  two  ^  inch  tees 
situated  on  opposite  sides  of  a  ^  inch  flange 
union,  substantially  as  shown  in  the  accompany- 
ing sketch.  A  thermometer  cup,  or  well,  is 
screwed  into  each  of  these  tees,  and  a  piece  of 
sheet  iron  perforated  with  a  yi  inch  hole  in  the 
center  is  inserted  between  the  flanges  and  made 


from  the  steam  main  to  the  1%  inch  pipe  is  well 
covered  with  hair  felt. 

Great  care  must  be  taken  that  the  }i  inch 
orifice  does  not  become  choked  with  dirt,  and 
that  no  leaks  occur,  especially  at  the  sheet  iron 
disc,  also  that  the  exhaust  pipe  does  not  produce 
any  back  pressure  below  the  flange.  Place  a 
thermometer  in  each  cup,  and,  opening  the  % 
inch  valve  wide,  let  steam  flow  through  the  in- 
strument for  ten  or  fifteen  minutes;  then  take 
frequent  readings  on  the  two  thermometers 
and  the  boiler  gauge,  say  at  intervals  of  one 
minute. 

The  throttling  calorimeter  depends  on  the 
principle  that  dry  steam  when  expanded  from  a 
higher  to  a  lower  pressure  without  doing  ex- 
ternal work  becomes  superheated,  the  amount 
of  superheat  depending  on  the  two  pressures. 
If,  however,  some  moisture  be  present  in  the 
steam,  this  must  necessarily  be  first  evaporated, 
and  the  superheating  will  be  proportionately 
less.  The  limit  of  the  instrument  is  reached 
when  the  moisture  present  is  sufficient  to  pre- 
vent any  superheating. 

Assuming  that  there  is  no  back  pressure  in 
the  exhaust,  and  that  there  is  no  loss  of  heat  in 
passing  through  the  instrument,  the  total  heat 
in  the  mixture  of  steam  and  moisture  before 
throttling,  and  in  the  superheated  steam  after 


79 


■* 


Washington  Life  Insurance  Company  Building,  New  York.      675  H.P.   Babcock  &  Wilcox  Boilers. 


throttling,  will   be  the  same,  and  will  be  ex- 
pressed by  the  equation 
X  L 


H- 


-=  1146.6  +  .48  (/ — •  212^ 


//— 1146.6  — .48  (/— 212) 
L 


X  100 


in  which  or  =  percentage  of  moisture;  //"=  total 
heat  above  32°  in  the  steam  at  boiler  pressure  ; 
L  =  latent  heat  in  the  steam  at  boiler  pressure  ; 
1 146. 6  =:  total  heat  in  the  steam  at  atmospheric 
pressure;  zf  =  temperature  shown  by  lower  ther- 
mometer of  calorimeter  ;  212  =  temperature  of 
dry  steam  at  atmospheric  pressure. 

Theoretically  the  boiler  pressure  is  indicated 
by  the  temperature  of  the  upper  thermometer, 
but  owing  to  radiation,  etc.,  it  is  usually  too  low, 
and  it  is  better  to  use  the  readings  of  the  boiler 
gauge,  if  correct,  or  better  still  to  have  a  test 
gauge  connected  on  the  yi  inch  pipe  supplying 
the  calorimeter. 

If  the  instrument  be  well  covered,  and  there 
is  as  little  radiating  surface  as  possible,  the  above 
assumption  that  there  is  no  loss  of  heat  in  pass- 
ing through  the  instrument  may  be  nearly,  though 
never  quite,  correct.  On  the  other  hand  it  is 
more  than  likely  to  be  very  far  from  correct,  and, 
to  eliminate  any  errors  of  this  kind,  Mr.  Barrus 
recommends  a  so-called  "calibration"  for  dry 
steam.  This,  again,  involves  an  assumption 
which  is  open  to  some  doubt,  which  is  that 
steam,  when  in  a  quiescent  state,  drops  all  its 
moisture  and  becomes  dry.  No  other  practical 
method,  however,  has  been  proposed,  and  this 
is,  therefore,  the  only  method  used  at  the  pres- 
ent time.  Some  engineers,  however,  refuse  to 
make  any  calibration,  but,  instead,  make  an  as- 
sumed allowance  for  error. 

To  make  the  calibration,  close  the  boiler  stop 
valve,  which  must  be^on  the  steam  pipe  beyond 
the  calorimeter  connection.  Keep  the  steam 
pressure  exactly  the  same  as  the  average  pres- 
sure during  the  test,  for  at  least  fifteen  minutes, 
taking  readings  from  the  two  thermometers  dur- 
ing the  last  five  minutes.  The  upper  thermome- 
ter should  read  precisely  the  same  as  during  the 
test,  and  the  lower  thermometer  should 
show  a  higher  temperature ;  this  reading 
of  the  lower  thermometer  is  the  calibra- 
tion reading  for  dry  steam,  which  we 
will  call  T. 

Calculation  of  results,  allowing  for 
radiation,  by  calibration  method:  — 
8  {T—t 


Formula     x 


thermometer  ;  t  =  test  read- 
ing of  lower  thermometer; 
L  =  latent  heat  of  steam  at 
boiler  pressure. 

The  method  of  taking  a 
sample  of  steam  from  the 
main  is  of  the  greatest  im- 
portance, and  more  erroneous 
results  are  due  to  improper 
connections  than  to  any  other 
cause.  The  sample  should 
be  taken  from  the  main  steam 
current  of  the  steam  ascend- 
ing in  a  vertical  pipe.  Avoid 
perforated  and  slotted  nip- 
ples, and  use  only  a  plain, 
open  ended  nipple  projectmg 
far  enough  into  the  steam 
pipe  to  avoid  collecting  any 
condensation  that  may  be  on 
the  sides  of  the  pipe.  Take 
care  that  no  pockets  exist  in 
the  steam  main  near  the  cal- 
orimeter in  which  condensa- 
tion can  collect  and  run  down 
into  sampling  nipple.  Make 
connections  as  short  as  possi- 
ble. 

As  mentioned  above,  there 
is  a  limit  in  the  range  of  the 
throttling  calorimeter  which 
varies  from2. 88%  at  sopounds 
pressure  to  7.17%  at  250 
pounds.  When  this  limit  is 
reachedasmall  separator  may 
be  interposed  between  the 
steam  main  and  the  calori- 
meter, which  will  take  out  the 
excess  of  moisture.  By  weigh- 
ing the  drip  from  the  separa- 
tor and  ascertaining  its  per- 


L 


X  100 


in  which  x  =  percentage  of  moisture ; 

T^^  calibration  reading  of  lower    Boiler  House  and  Chimney  lor  Babcock  &  Wilcox  Boiler  with  Economizer,  etc. 


81 


-KH 


►i^ 


■* 


^ 


centage  of  the  steam  flowing  through,  and  add- 
ing this  to  the  percentage  of  moisture  then  shown 
by  the  throttHng  calorimeter,  the  total  moisture 
in  the  steam  may  be  ascertained.  It  is  seldom, 
however,  in  a  well  designed  boiler  that  any  but 
a  throttling  calorimeter  becomes  necessary. 


RIVETED    JOINTS. 

The  strength  of  a  riveted  joint  is  dependent 
on  —  first,  the  section  of  plate  remaining  after 
deducting  the  diameter  of  the  rivet  holes  and  — 
second,  on  the  strength  in  shear  of  the  rivets. 

Let  d  =  diameter  of  rivet  after  driving  in  inclies. 
a  =  area  of  one  rivet  in  square  inches. 
/  =  pitchi  of  rivets  in  inches. 
n  =  number  of  rows  of  rivets. 
i  =  tliickness  of  sliell  in  iuclnes. 
J?  =  internal  radius  of  drum  in  inclies. 
T=  tensile  strength  of  plates  per  square  inch  in  pounds. 
S  =  shearing  strength  of  rivets  per  square  inch  in  pounds, 
y  =  factor  of  safety. 

Then,  to  find  the  strength  of  a  plate  between 
rivets  in  percentage  of  the  full  plate  : — 


(I) 


P 


P 


To  find  value  of    the   shearing  strength   of 
rivet  in  percentage  of  plate  : — 
«■  X  «  X  5 


(2) 


P' 


pXtXT 

To  find    the  pressure  which    a    drum  with 

seams  designed  by  the  foregoing  formulae  will 

endure,  select  the  smaller  of  the  results  P  and 

P'  obtained  by  formulae  i  and  2,  and  designate 

this  as  V.     Then 

t  y.  TX  V 

—  — =  pounds  per  sq.in.  internal  pressure. 

J<  X  J 

In  designing  joints  with  two  cover  plates  at 
least  a  part  of  the  rows  of  rivets  will  be  in 
double  shear.  A  rivet  in  double  shear  is  gen- 
erally considered  as  1.75  times  its  value  in 
single  shear.  Take,  this  into  consideration  in 
counting  up  the  number  of  rows  of  rivets  for 
such  joints. 

A  joint  may  be  highly  efficient  in  strength 
and  fail  to  be  tight.  The  tightness  of  a  joint 
depends  on  the  rivet  spacing  and  the  thickness 
of  the  caulking  edge.  For  this  reason  a  cover 
plate  thicker  than  is  required  for  strength  can 
be  used  with  good  results. 


FEEDING  BOILERS. 

The  relative  value  of  injectors,  direct-acting 
steam  pumps,  and  pumps  driven  from  the  engine, 
is  a  question  of  importance  to  all  steam  users. 
The  following  table  has  been  calculated  by  D.  S. 
Jacobus,  M.  E.,  from  data  obtained  by  experi- 
ment.    It  will  be  noticed  that  when  feeding  cold 


water  direct  to  boilers,  the  injector  has  a  slight 
economy,  but  when  feeding  through  a  heater  a 
pump  is  much  the  most  economical. 


Method  of  Supplying  Feed- 
Water  to  Boiler. 
Temperature  of  feed-water 
asdeliveredto  thepun-.p  orto 
the  injector,  Go'^  Fah.  Rate 
of  evaporatio  1  of  boiler,  lo 
pounds  of  water  per  pound 
of  coal  from  and  at  212'-'  Fah. 


Direct  acting  pump  feeding 
water  at  60°,  without  a 
heater, 

Injector  feeding  water  at 
150°,  without  a  heater,    . 

Injector  feeding  through  a 
heater  in  which  the  water 
is  heated  from  150  to  200°, 

Direct  acting  pump  feeding 
water  through  a  heater,  in 
which  it  is  heated  from 
60  to  200"^, 

Geared  pump,  run  from  the 
engine,  feeding  water 
through  a  heater,  in  which 
it  is  heated  fnjm  60  to  200°, 


Relative  amount  of  ^^^-       „f  ^^^■^^ 
coal  required  per  I       ^vlr  the 
unit  of  time,  the   I        a.no^nt 
amount  for  a  direct  required  when 
acting  pump,  leed       - 
ing  water  at  60"^, 
without  a  heater, 
being  taken  as 
unity. 


the  boiler  is 
fed  by  a  direct 

acting  pump 
without  heater. 


1.5  per  cent. 
6.2  per  cent. 

12. 1  per  cent. 

13.2  per  cent. 


ECONOMY  OF  HIGH  PRESSURE  STEAM. 

Higher  steam  pressure  is  the  tendency  of  the 
times,  and  with  good  reason,  for  the  higher  the 
pressure  the  greater  the  opportunity  for  economy 
in  generating  power.  The  compound  and  triple 
expansion  engines  of  the  present  day,  which  have 
reduced  the  cost  of  power  some  40  per  cent,  over 
the  best  performance  of  a  few  years  ago,  require 
higher  pressure  than  can  with  safety  be  carried 
on  shell  boilers,  but  there  is  no  difficulty  in 
carrying  any  desirable  pressure  on  a  sectional 
water-tube  boiler  properly  constructed.  Babcock 
&  Wilcox  boilers,  in  special  cases,  carry  as  high 
as  500  pounds  pressure  in  regular  work. 


HEATING  FEED-WATER. 

The  feed-water  furnished  to  steam  boilers  has 
to  be  heated  from  the  normal  temperature  to 
that  of  the  steam  before  evaporation  can  com- 
mence, and  this  generally  at  the  expense  of  the 
fuel  which  should  be  utilized  in  making  steam. 
This  temperature  at  75  lb.  pressure  is  320°,  and 
if  we  take  60°  as  the  average  temperature  of  feed, 
we  have  260  units  of  heat  per  pound,  w^hich,  as 
it  takes  1.151  units  to  evaporate  a  pound  from 
60°,  represents  22.5  per  cent,  of  the  fuel.  All  of 
this  heat,  therefore,  which  can  be  imparted  to 
the  feed-water  is  just  so  much  saved,  not  only 
in  cost  of  fuel,  but  in  capacity  of  boiler.  But  it  is 
essential  that  it  be  done  by  heat  which  would 
otherwise  be  wasted.  All  heat  imparted  to  feed- 
water  by  injectors  and  "live-steam  heaters" 
comes  from  the  fuel  and  represents  no  saving. 


^ 


83 


-►H 


4- 


There  are  two  sources  of  vviiste  heat  available 
for  this  purpose  —  exhaust  steam  and  chimney 
gases.  By  the  former,  water  may  be  heated  to 
200°,  or  possibly  to  210°,  in  a  well-proportioned 
heater. 

The  gases  going  to  the  chimney  carry  off  on 
an  average,  according  to  good  authority,  51  per 
cent,   of  the  fuel,   and  in  the  most  economical 


boiler  this  cannot  be  reduced  below  12  per  cent. 
Some  proportion  of  this  is  always  available  for 
heating  the  feed-water,  by  what  are  known  as 
' '  economizers, ' '  and  frequently  it  may  be  carried 
nearly  to  the  temperature  of  high  pressure  steam, 
making  a  saving  in  some  instances  of  20  per 
cent.  The  more  wasteful  the  boiler,  the  greater 
the  benefit  of  the  economizer  ;  but  for  large 
plants  it  is  always  a  valuable  adjunct.  In  many 
cases  water  heated  by  exhaust  steam  may  be 
still  further  heated  in  an  economizer  to  advan- 
tage. 


Babcock  &  Wilcox  Boilers  at  Solvay  Process  Co.'s,    3,264  H.P.,  set  with  Independent  Feed-Water  Heaters. 

20,154  H.P.  now  in  use. 


SAVING   OF   FUEL   BY   HEATING  FEED-WATER.      (IN   PER   CENT.,  STEAM   AT   60   POUNDS.) 


Initial 

FINAL    TEMPERATURE 

OF    FEED-WATER. 

Initial 

FINAL    TEMPERATURE 

OF    FEED-WATER. 

Temperature 

of  Water. 

120 

140 

160 

180 

200 

250 

300 

of  Water. 

120 

140 

160 

180 

200 

250 

300 

32° 

7.50 

9.20 

10.  go 

12.36 

14,30 

19,03 

22.90 

go°            2 

.68 

4-47 

6.26 

8.06 

9-85 

14.32 

18.81 

35 

7 

25 

8 

9b 

10 

bb 

12. og 

14.09 

1834 

22.60 

95              2 

•24 

4.04 

5-S4 

7 

65 

9 

44 

13 

94 

18 

44 

40 

b 

ss 

8 

57 

10 

28 

12.00 

13-7' 

17.99 

22.27 

100              1 

.80 

3.bi 

5-42 

7 

23 

9 

03 

13 

55 

18 

07 

45 

6 

4S 

8 

17 

9 

90 

II. 61 

13-34 

17 

64 

21.94 

no 

.90 

2-73 

4-55 

6 

3« 

8 

20 

12 

7b 

17 

28 

50 

b 

05 

7 

71 

9 

50 

11.23 

13.00 

17 

28 

21.61 

120 

0 

1.84 

3-67 

5 

52 

7 

36 

II 

95 

lb 

49 

55 

5 

b4 

7 

37 

9 

ob 

10.85 

13.60 

lb 

93 

21.27 

130 

.92 

2-77 

4 

H 

6 

99 

II 

14 

15 

24 

60 

5 

23 

6 

97 

8 

72 

10.46 

12.20 

16 

5« 

20.92 

140 

0 

1.87 

3 

75 

5 

b2 

10 

31 

14 

99 

65 

4 

82 

b 

56 

8 

32 

10.07 

11.82 

16 

20 

20.58 

150 

•94 

2 

«3 

4 

72 

9 

46 

14 

18 

70 

4 

40 

b 

15 

7 

91 

9. 68 

11-43 

15 

«3 

20.23 

160 

0 

I 

91 

3 

82 

8 

59 

13 

37 

75 

?. 

q« 

S 

74 

7 

50 

9.28 

11.04 

15 

46 

19. 88 

170 

gb 

2 

89 

7 

71 

12 

54 

So 

3 

55 

5 

32 

7 

09 

8:87 

10.65 

15 

08 

19.52 

180 

0 

I 

gb 

6 

81 

II 

70 

85 

3.12 

4.90 

6.63 

8.46 

ro.25 

14 

70 

19.17 

200 

0 

485 

9-93 

^ 


85 


i 


m 


SUPERHEATED   STEAM. 

Steam  which  has  a  higher  temperature  than 
that  normal  to  its  pressure  is  termed  ' '  super- 
heated" or  "gaseous." 

Of  the  sources  of  waste  in  an  engine,  the 
condensation  of  steam  from  the  cooling  effects 
of  the  cylinder  walls,  or  cylinder  condensation 
as  it  is  called,  is  by  far  the  greatest.  This  was 
recognized  even  early  in  the  present  century, 
but  in  1855,  for  the  first  time,  the  extent  of  this 
loss  was  established  in  a  definite  manner,  by 
Hirn.  In  more  recent  years,  Professor  Dwel- 
shauvers-Dery,  Mr.  Walther  Meunier,  of  the 
Alsatian  Association  of  Steam  Users,  Professor 
William  C.  Unvvin,  and  others,  have  given  much 
of  their  time  and  thought  to  this  question. 

It  has  been  established,  practically,  that  in  an 
ordinary  single  cylinder  non-condensing  engine, 
the  amount  of  waste  through  cylinder  conden- 
sation amounts,  with  an  early  cut-off,  to  35  to 
40  per  cent,  of  the  total  steam  used. 

The  best  means  of 
partially  or  wholly  pre- 
venting this  loss  is  by  the 
use  of  superheated  steam. 

Steam  is  said  to  be 
superheated  when,  at  any 
given  boiler  pressure,  it 
has  a  higher  temperature 
than  the  water  from  which 
it  was  evaporated. 

Water,  no  matter  from 
what  cause  arising,  can- 
not exist  in  the  presence 
of  superheated  steam ,;  it 
robs  the  steam  of  its  extra 
heat,  and  is  itself  evapo- 
rated into  steam. 

The  temperature  of  sat- 
urated  steam   cannot  be 

raised  without  increasing  its  pressure  ;  but 
the  temperature  of  superheated  steam  allowed 
to  expand  can  be  raised  without  increasing  the 
pressure.  Expansion  is  provided  for  by  the 
steam  being  drawn  off  and  used,  or,  if  no  steam 
is  used,  by  the  safety  valve  lifting.  We  mention 
this  to  prevent  any  erroneous  impression  that 
superheating  steam  causes  the  production  of 
excessive  pressures  in  boilers,  and  consequently 
entails  more  danger  in  ordinary  working. 

From  time  to  time  various  attempts  have  been 
made  to  supply  superheated  steam  to  engines, 
both  on  land  and  on  board  ship.  In  the  latter 
connection,  Mr.  John  Penn,  the  famous  engineer, 
made  many  trials,  and  stated,  in  his  papers  read 
before  the  Institution  of  Mechanical  Engineers 


heat,  an  economy  of  20  to  30  per  cent,  in  fuel 
consumption  was  obtained  on  some  of  the 
steamers  in  which  superheating  was  adopted. 

At  that  time  the  application  of  superheaters 
was  spasmodic,  due  to  mechanical  defects  in 
the  superheaters  themselves  or  in  their  applica- 
tion. They  were  frequently  placed  in  the  up- 
takes of  marine  boilers,  where  they  were  not 
sufficiently  protected  from  the  corrosive  action 
of  the  gases  condensed  after  leaving  the  boilers. 
In  other  instances  the  inaccessibility  of  their 
position  caused  them  to  incur  disfavor,  and 
the  lack  of  suitable  oils  for  engine  cylinder 
lubrication  increased  the  difficulties. 

The  "  rationale "  of  the  use  of  superheated 
steam  is  not  only  the  prevention  of  loss  through 
condensation  in  steam  pipes,  but  the  addition 
of  such  an  amount  of  superheat  to  the  steam, 
before  it  enters  the  cylinder,  as  will  make  up 
for  that  robbed  by  the  cylinder  walls,  so  that 
the  steam  will  remain  practically  dry,  at  all 
events  up  to  the  point  of 
cut-off. 
J_     ~  Bearing   in   mind  what 

^  ^*N^  has    already   been  done, 

we  find  that  the  princi- 
ples on  which  a  super- 
heater should  be  con- 
structed, to  give  a  suffi- 
ciently high  temperature, 
are  :  — 

First.  —  The  necessity 
of  placing  the  superheater 
in  a  position  where  a  suit- 
able temperature  is  avail- 
able. If  a  boiler  is  work- 
ing under  economical 
conditions,  the  difference 
between  the  temperature 
of  saturated  steam  and  of 
the  escaping  fine  gases  leaving  a  boiler  is  not 
sufficient  to  superheat  the  steam  produced, 
unless  the  surface  of  the  superheater  be  very 
large  :  hence,  generally  speaking,  a  superheater 
should  not  be  placed  in  the  flue  between  boiler 
and  chimney.  On  the  other  hand,  if  placed  too 
near  to  the  boiler  furnace,  or  in  a  separate 
furnace,  considerable  temperature  fluctuations 
may  occur,  and  possibly  an  excessive  tempera- 
ture may  be  attained  which  would  cause  damage. 
Secondly. — The  superheater  should  be  con- 
structed to  admit  of  all  its  parts  expanding  and 
contracting  freely,  without  severe  strains  being 
put  on  any  of  the  joints,  which  might  cause 
them  to  leak  ;  flanged  joints,  when  exposed  to 
furnace    gases,    should    be    avoided    wherever 


in  1859-1860,  that  with  100°  to  120°  F.  of  super-      possible. 


87 


Thirdly. — Provision  should  be  made  to  pro- 
tect the  superheater  against  overheating  when 
steam  is  not  passing  through  it  sufficiently  to 
carry  away  the  heat  supplied  by  the  furnace 
gases. 

It  will  be  seen  from  the  illustration  that  the 
Patent  Superheater  fuliills  all  these  conditions. 
It  is  placed  in  a  position  where  there  is  prac- 
tically no  deteriorating  condensation  of  the 
gases,  and  where  the  temperature  is  sufficiently 
high  to  insure  the  steam  receiving  from  ioo°  to 
150°  F.  of  superheat. 

This  superheater  is  not  subject  to  the  imme- 
diate action  of  the  fire,  as  the  furnace  gases 
must  first  pass  through  the  front  part  of  the 
boiler,  which  comprises  a  considerable  heating 
surface.  Assuming  the  boiler  to  be  in  regular 
work,  and  the  firing  even,  no  great  fluctuations 
in  temperature  can  take  place  where  the  super- 
heater is  fixed.  Moreover,  it  is  readily  accessi- 
ble for  examination,  and  for  the  renewal  of 
tubes. 

There  are  no  flanged  joints,  all  the  tube  joints 
are  expanded. 

Freedom  for  expansion  is  provided  for  by  the 
tubes  being  free  at  one  end,  and  by  the  mani- 
folds not  being  rigidly  connected  with  each 
other. 

Prevention  against  overheating  during  steam 
raising  is  insured  by  the  arrangement  for  flood- 
ing with  boiler  water,  and  using  the  superheater 
as  part  of  the  boiler  heating  surface,  whilst 
steam  is  being  raised,  or  when  it  is  desired  to 
use  saturated  steam. 

As  will  be  seen,  the  tubes  are  bent  into 
a  "U"  shape,  and  connected  at  both  ends 
with  manifolds,  one  of  which  receives  the  nat- 
ural steam  from  the  boiler,  the  other  collecting 
the  superheated  steam  after  it  has  traversed  the 
superheater  tubes,  and  delivering  it  to  the  valve, 
placed  above  the  boiler. 

The  flooding  arrangement  consists  merely  in 
a  connection  with  the  water  space  of  the  boiler 
drum,  and  a  three-way  cock,  by  which,  at  will, 
the  water  enters  the  lower  manifold  and  fills  the 
superheater  to  the  boiler  water  level.  Any 
steam  formed  in  the  superheater  tubes  is  re- 
turned into  the  boiler  drum,  through  the  col- 
lecting pipe,  which,  when  the  superheater  is  at 
work,  conveys  saturated  or  natural  steam  into 
.  the  upper  manifold.  Prior  to  opening  the  super- 
heater stop  valve  and  using  superheated  steam, 
the  water  is  drained  away  from  the  manifolds 
by  the  flooding  pipe. 

The  water  in  the  boiler  steam  and  water  drum 
is,  by  reason  of  the  fact  that  it  is  heated  to 


steam  temperature,  deprived  of  its  impurities, 
hence  there  is  no  fear,  in  flooding  the  super- 
heater with  the  boiler  water,  of  the  superheater 
tubes  becoming  incrustated  to  any  detrimental 
extent. 

A  considerable  number  of  these  superheaters 
have  now  been  at  work  for  some  time,  and  the 
results  lead  to  the  expectation  that  their  dura- 
bility will  leave  nothing  to  be  desired. 

From  100°  to  150°  F.  of  superheat  is  usually 
provided  for  in  the  proportion  of  superheating 
surface  to  boiler  heating  surface  adopted,  and 
it  has  been  found  by  experiment  that  even  with 
the  most  refined  triple  expansion  engines,  work- 
ing under  ordinary  conditions,  an  economy  of 
from  ID  to  15  per  cent,  can  be  regularly  ob- 
tained. With  engines  less  refined,  or  of  slower 
piston  speed,  of  course  the  percentage  of  saving 
is  greater. 

The  use  of  the  superheater  goes  a  long  way 
to  assist  engineers  to  fulfill  the  task  of  the 
present  times,  namely,  to  produce  a  horse- 
power with  a  pound  of  coal. 

Professor  R.  H.  Thurston,  in  a  recent  paper 
before  the  American  Society  of  Mechanical 
Engineers,  on  Superheated  Steam,  arrives  at  the 
following  conclusions  :  — 

1.  Superheated  steam,  as  hitherto  employed 
in  the  steam  engine,  has  absolutely  no  thermo- 
dynamic value,  that  is,  it  neither  raises  the 
upper  limit  of  temperature  or  depresses  the 
lower  limit. 

2.  Superheating  has  for  its  sole  purpose  and 
result,  in  the  steam  engine  to-day,  the  extinc- 
tion or  reduction  of  the  internal  thermal  wastes 
of  the  engine,  consequent  upon  the  phenome- 
non known  as  initial  or  ' '  cylinder  condensa- 
tion." Here  it  is  extraordinarily  effective,  and 
a  small  quantity  of  heat  expended  in  superheat- 
ing the  entering  steam  effects  a  comparatively 
large  reduction  in  the  expenditure  of  steam  in 
the  engine. 

3.  Superheating  is  superior  to  any  other 
known  means  of  reduction  of  internal  waste. 

4.  No  trouble  need  now  be  found  at  the 
engine  with  sufficient  superheating  under  usual 
conditions  of  operation,  to  annihilate  cylinder 
condensation. 

5.  The  more  wasteful  the  engine,  the  larger 
the  promise  of  gain  by  superheating,  and  small 
engines  will  profit  by  it  more  than  large,  slow 
engines  more  than  fast,  and  single  engines 
more  than  the  multiple-cylinder  systems. 

6.  The  larger  the  waste  to  be  checked  in  the 
engine,  the  farther  should  the  superheating  be 
carried. 


INCRUSTATION  AND  SCALE. 

Nearly  all  waters  contain  foreign  substances  in 
greater  or  less  degree,  and,  though  this  may  be  a 
small  amount  in  each  gallon,  it  becomes  of  im- 
portance where  large  quantities  are  evaporated. 
For  instance,  a  loo  H.  P.  boiler  evaporates  30,- 
000  pounds  water  in  ten  hours,  or  390  tons  per 
month;  in  the  comparatively  pure  Croton  water 
there  would  be  88  pounds  of  solid  matter  in  that 
quantity,  and  in  many  kinds  of  spring  water  as 
much  as  2,000  pounds. 

The  nature  and  hardness  of  the  scale  formed 
of  this  matter  will  depend  upon  the  kind  of  sub- 
stances held  in  solution  and  suspension.  Analy- 
ses of  a  great  variety  of  incrustations  show  that 
carbonate  and  sulphate  of  lime  form  the  larger 
part  of  all  ordinary  scale,  that  from  carbonate 
being  soft  and  granular,  and  that  from  sulphate 
hard  and  crystalline.  Organic  substances  in  con- 
nection with  carbonate  of  lime  will  also  make  a 
hard  and  troublesome  scale. 

The  presence  of  scale  or  sediment  in  a  boiler 
results  in  loss  of  fuel,  burning  and  cracking  of 
the  boiler,  predisposes  to  explosion,  and  leads  to 
extensive  repairs.  It  is  estimated  that  the  pres- 
ence of  jJg  inch  of  scale  causes  a  loss  of  13  per 
cent,  of  fuel,  X  inch  38  per  cent. ,  and  %  inch  60 
per  cent.  The  Railway  Master  Mechanics'  Asso- 
ciation of  the  U.  S.  estimates  that  the  loss  of  fuel, 
extra  repairs,  etc.,  due  to  incrustation,  amount 
to  an  average  of  ^750  per  annum  for  every  loco- 
motive in  the  Middle  and  Western  States,  and  it 
must  be  nearly  the  same  for  the  same  power  in 
stationary  boilers. 

The  most  common  and  important  minerals  in 
boiler  scale  are  carbonate  of  lime,  sulphate  of 
lime,  and  carbonate  of  magnesia.  Small  amounts 
of  alumina  and  silica  are  sometimes  found,  and 
an  oxide  of  iron  not  infrequently  is  present  as  a 
coloring  matter.    ■ 

Means  of  Prevention. 

It  is  absolutely  essential  to  the  successful  use 
of  any  boiler,  except  in  pure  water,  that  it  be  ac- 
cessible for  the  removal  of  scale,  for  though  a 
rapid  circulation  of  water  will  delay  the  deposit, 
and  certain  chemicals  will  change  its  character, 
yet  the  most  certain  cure  is  periodical  inspection 
and  mechanical  cleaning.  This  may,  however, 
be  rendered  less  frequently  necessary,  and  the 
use  of  very  bad  water  more  practical,  by  the  em- 
ployment of  some  preventives.  The  following  are 
a  fair  sample  of  those  in  use,  with  their  results:  — 

M.  Bidard's  observations  show  that  "  anti- 
incrustators ' '  containing  organic  matter  help 
rather  than  hinder  incrustations,  and  are  there- 
fore to  be  avoided. 


Oak,  hemlock,  and  other  barks  and  woods, 
sumac,  catechu,  logwood,  etc.,  are  effective  in 
waters  containing  carbonates  of  lime  or  magne- 
sia, by  reason  of  their  tannic  acid,  but  are  injuri- 
ous to  the  iron,  and  not  to  be  recommended. 

Molasses,  cane  juice,  vinegar,  fruits,  distillery 
slops,  etc. ,  have  been  used  with  success  so  far  as 
scale  is  concerned,  by  reason  of  the  acetic  acid 
which  they  contain,  but  this  is  even  more  injuri- 
ous to  the  iron  than  tannic  acid,  while  the  or- 
ganic matter  forms  a  scale  with  sulphate  of  lime 
when  it  is  present. 

Milk  of  lime  and  metallic  zinc  have  been  used 
with  success  in  waters  charged  with  bicarbonate 
of  lime,  reducing  the  bicarbonate  to  the  insolu- 
ble carbonate. 

Barium  chloride  and  milk  of  lime  are  said  to 
be  used  with  good  effect  at  Krupp's  Works,  in 
Prussia,  for  waters  impregnated  with  gypsum. 

Soda  ash  and  other  alkalies  are  very  useful  in 
waters  containing  sulphate  of  lime,  by  convert- 
ing it  into  a  carbonate,  and  so  forming  a  soft 
scale  easily  cleaned.  But  when  used  in  excess 
they  cause  foaming,  particularly  where  there  is 
oil  coming  from  the  engine,  with  which  they 
form  soap.  All  soapy  substances  are  objection- 
able for  the  same  reason. 

Petroleum  has  been  much  used  of  late  years. 
It  acts  best  in  waters  in  which  sulphate  of  lime 
predominates.  As  crude  petroleum,  however, 
sometimes  helps  in  forming  a  very  injurious 
crust,  the  refined  only  should  be  used. 

Tannate  of  soda  is  a  good  preparation  for  gen- 
eral use,  but,  in  waters  containing  much  sulphate, 
it  should  be  supplemented  by  a  portion  of  car- 
bonate of  soda  or  soda  ash. 

A  decoction  from  the  leaves  of  the  eucalyptus 
is  found  to  work  well  in  some  waters,  in  Cali- 
fornia. 

For  muddy  water,  particularly  if  it  contain  salts 
of  lime,  no  preventive  of  incrustation  will  prevail 
except  filtration,  and  in  almost  every  instance 
the  use  of  a  filter,  either  alone  or  in  connection 
with  some  means  of  precipitating  the  solid  mat- 
ter from  solution,  will  be  found  very  desirable. 

In  all  cases  where  impure  or  hard  waters  are 
used,  frequent  ' '  blowing  ' '  from  the  mud-drum 
is  necessary  to  carry  off  the  accumulated  matter, 
which  if  allowed  to  remain  would  form  scale. 

When  boilers  are  coated  with  a  hard  scale  diffi- 
cult to  remove,  it  will  be  found  that  the  addition 
of  X  pound  caustic  soda  per  horse-power,  and 
steaming  for  some  hours,  according  to  the  thick- 
ness of  the  scale,  just  before  cleaning,  will  greatly 
facilitate  that  operation,  rendering  the  scale  soft 
and  loose.  This  should  be  done,  if  possible, 
when  the  boilers  are  not  otherwise  in  use. 


►  ■+■ 


89 


^ 


■* 


^.-4- 


H EATING  FROM  CENTRAL  STATIONS. 

It  has  been  thoroughly  demonstrated,  by 
practice,  that  a  number  of  buildings  may  be 
heated  from  a  single  central  plant,  instead  of  its 
being  necessary  to  place  a  boiler  in  each.  This 
is  a  simple  problem  where  the  buildings  form  a 
group,  as  at  Columbia  College,  in  New  York 
city,  Cornell  University,  Ithaca,  N.  Y.,  Vander- 
bilt  University,  Nashville,  Tenn.,  the  Indiana 
State  Asylums  for  the  Insane,  and  many  other 
similar  institutions,  where  a  single  plant  of 
Babcock  &  Wilcox  boilers  supply  heat  and  power 
to  a  number  of  detached  buildings.  It  has  also 
been  attempted  in  a  number  of  places  to  carry 
steam,  as  gas  and  water  are  supplied.  Though 
a  number  of  these  attempts  have  been  failures. 


continuously,  with  a  minimum  amount  of  stop- 
page for  repairs;  and,  above  all,  they  should  be 
so  constructed  as  to  be  safe  against  destructive 
explosion.  The  ability  to  furnish  dry  steam  is 
also  a  very  important  point,  where  it  is  intended 
to  carry  it  through  so  many  miles  of  pipe  before 
it  is  finally  used  up.  The  boiler  adopted  was  the 
Babcock  &  Wilcox  Water-tube  Boiler. 


HEATING  BY  STEAM. 

In  heating  buildings  by  steam,  the  amount  of 
boiler  and  heating  pipe  depends  largely  on  the 
kind  of  building  and  its  location.  Wooden  build- 
ings require  more  than  stone,  and  stone  more 
than  brick.  Iron  fronts  require  still  more,  and 
glass  in  windows  demands  twenty  times  as  much 


Northern  Hospital  for  the  Insane,  Logansport,  Ind.,  with  400  H.P.  of  Babcock  &  Wilcox  Boilers.     Erected  1885. 


the  experience  of  the  New  York  Steam  Co.,  the 
most  extensive  of  'such  plants  yet  constructed, 
has  fully  demonstrated  that  it  is  possible  to  thus 
carry  steam  for  miles,  with  no  serious  losses,  and 
that  private  houses  and  business  places  may  be 
thus  supplied  regularly  with  steam,  at  reduced 
cost  to  them,  and  at  a  profit  to  the  producer. 
This  company  have,  at  present,  three  stations  in 
operation,  one  of  which  is  doubtless  the  largest 
single  plant  of  stationary  boilers  in  the  world, 
—  i2,ooo  H.  P.,  under  one  roof, —  supplying 
steam,  through  seventeen  miles  of  pipe,  laid 
in  the  streets. 

In  a  work  of  this  magnitude  it  becomes  abso- 
lutely imperative  that  the  boilers  which  furnish 
the  steam  should  be  of  such  a  construction  as  to 
give  the  greatest  amount  of  useful  effect  for  the 
coal  burned,  and  at  the  same  time  be  able  to  run 


heat  as  the  same  surface  in  brick  walls.  Also  if 
the  heating  be  done  by  indirect  radiation  from  50 
to  100  per  cent,  more  surface  will  be  required 
than  when  direct  radiation  is  used.  No  rules  can 
be  given  which  will  not  require  a  liberal  applica- 
tion of  ^'  the  co-efficient  of  common  sense." 

Radiating  surface  may  be  calculated  by  the 
rule :  Add  together  the  square  feet  of  glass  in 
the  windows,  the  nuinber  of  cubic  feet  of  air 
required  to  be  changed  per  minute,  and  one- 
twentieth  the  surface  of  external  wall  and  roof  ; 
multiply  this  sum  by  the  difference  between  the 
required  temperature  of  the  room  and  that  of 
the  external  air  at  its  lowest  point,  and  divide 
the  product  by  the  differe?ice  in  temperature 
between  the  steam  in  the  pipes  and  the  required 
temperature  of  the  room.  The  quotient  is  the 
required  radiating  surface  in  square  feet.     Each 


4^ 


91 


^A 


I 


Waldorf-Astoria  Hotel,  New  York.        2257  H.P.   Babcock  &  Wilcox  Boilers. 


square  foot  of  radiating  surface  may  be  depended 
upon  in  average  practice  to  give  out  tliree  lieat 
units  per  hour  for  each  degree  of  difference  in 
temperature  between  the  steam  inside  and  the 
air  outside,  the  range  under  different  conditions 
being  about  50  per  cent,  above  or  below  that 
figure.  In  indirect  heating,  the  efficiency  of 
the  radiating  surface  will  increase,  and  the  tem- 
perature of  the  air  will  diminish,  when  the  quan- 
tity of  the  air  caused  to  pass  through  the  coil  in- 
creases.   Thus  one  square  foot  radiating  surface, 


tional  surface  should  be  allowed,  and  for  three 
times  the  diameter,  30  per  cent,  additional  is 
required.  For  indirect  radiation  that  surface  is 
most  efficient  which  secures  the  most  intimate 
contact  of  the  current  of  air  with  the  heated  sur- 
face. Rooms  on  windward  side  of  house  require 
more  radiating  surface  than  those  on  sheltered 
side. 

Where  the  condensed  water  is  returned  to  the 
boiler,  or  where  low  pressure  of  steam  is  used, 
the  diameter  of  mains  leading  from  the  boiler  to 


Riveting  Drum  Heads  at  Babcock  &  Wilcox  Shop. 


with  steam  at  212°,  has  been  found  to  heat  100 
cubic  feet  of  air  per  hour  from  zero  to  150°,  or 
300  cubic  feet  from  zero  to  100°  in  the  same  time. 

The  best  results  are  attained  by  using  indirect 
radiation  to  supply  the  necessary  ventilation, 
and  direct  radiation  for  the  balance  of  the  heat. 
The  best  place  for  a  radiator  in  a  room  is  beneath 
a  window.  Heated  air  cannot  be  made  to  enter 
a  room  unless  means  are  provided  for  permitting 
an  equal  amount  to  escape.  The  best  place  for 
such  exit  openings  is  near  the  floor. 

Small  pipes  are  more  effective  than  large. 
When  the  diameter  is  doubled,  20  per  cent,  addi- 


the  radiating  surface  should  be  equal,  in  inches, 
to  one-tenth  the  square  root  of  the  radiating  sur- 
face, mains  included,  in  square  feet.  Thus  a 
I  inch  pipe  will  supply  100  square  feet  of  surface, 
itself  included.  Return  pipes  should  be  at  least 
j{  inches  in  diameter,  and  never  less  than  one- 
half  the  diameter  of  the  main  — ■  longer  returns 
requiring  larger  pipe.  A  thorough  drainage  of 
steam  pipes  will  effectually  prevent  all  cracking 
and  pounding  noises  therein. 

The  amount  of  air  required  for  ventilation  is 
from  4  to  16  cubic  feet  per  minute  for  each  per- 
son, the  larger  amount  being  for  prisons  and  hos- 


*i^ 


92 


*■ 


*b 


^ 


pitals.  From  >^  to  i  cubic  foot  per  minute 
should  be  allowed  for  each  lamp  or  gas  burner 
employed. 

One  square  foot  of  boiler  surface  will  supply 
from  7  to  lo  square  feet  of  radiating  surface,  de- 
pending upon  the  size  of  boiler  and  the  efificiency 
of  its  surface,  as  well  as  that  of  the  radiating 
surface.  Small  boilers  for  house  use  should  be 
much  larger  proportionately  than  large  plants. 
Each  horse-power  of  boiler  will  supply  from  240 
to  360  feet  of  i-inch  steam  pipe,  or  from  80  to  120 
square  feet  of  radiating  surface. 

Cubic  feet  of  space  has  little  to  do  with  amount 
of  steam  or  surface  required,  but  is  a  convenient 
factor  for  rough  calculations.  Under  ordinary 
conditions  one  horse-power  will  heat,  approx- 
imately, in 

-Brick  dwellings,  in  blocks,  as  in  cities,  15,000  to  20,000  cub. ft. 

Brick  stores,  in  blocks, 10,000  to  15,000  cub.ft. 

Brick  dwellings,  exposed  all  round,      .  10,000  to  15,000  cub.ft. 

Brick  mills,  shops,  factories,  etc.,   .     .  7,000  to  10,000  cub.ft. 

Wooden  dwellings,  exposed,       .     .     .  7,000  to  10,000  cub.ft. 

Foundries  and  wooden  shops,     .     .     .  6,000  to  10,000  cub.ft. 

Exhibition  buildings,  largely  glass,  etc.,  4,000  to  15,000  cub.ft. 

The  system  of  heating  mills  and  manufactories 
by  means  of  pipes  placed  overhead,  is  being 
largely  adopted,  and  is  recommended  by  the 


Boston  Manufacturers'  Mutual  Fire  Ins.  Co.  in 
preference  to  radiators  near  the  floor,  particu- 
larly for  rooms  in  which  there  are  shafting  and 
belting  to  circulate  the  air. 

In  heating  buildings  care  should  be  taken  to 
supply  the  necessary  moisture  to  keep  the  air 
from  becoming  "dry"  and  uncomfortable.  The 
capacity  of  air  for  moisture  rises  rapidly  as  it  is 
heated,  it  being  four  times  as  great  at  72°  as  at 
32°.  For  comfort,  air  should  be  kept  at  about 
"  50  per  cent,  saturated."  This  would  require 
one  pound  of  vapor  to  be  added  to  each  2,500 
cubic  feet  heated  from  32°  to  70°. 

A  much  needed  attachment  has  recently  been 
introduced,  which  acts  automatically  upon  the 
steam  valves  of  the  radiators,  or  upon  the  hot 
air  registers  and  ventilators,  and  maintains  the 
temperature  in  a  room  to  within  one-half  a  de- 
gree of  any  standard  desire. 

A  ' '  separator ' '  acting  by  centrifugal  force  has 
been  recently  tested,  and  is  very  efficient,  in 
trapping  out  all  the  water  entrained  in  steam. 
It  will  be  found  valuable,  particularly  where  the 
steam  has  to  be  carried  a  long  distance  from  the 
boiler,  and  for  the  purpose  of  preventing  "ham- 
mering "  of  water  in  the  pipes. 


Boilers,  Boiler  House,  and  Economizers,  with  Blast  Flue  and  Ash  Tunnel,  made  for  Lombard,  Ayres  &  Co., 
Seaboard  Oil  Refinery,  Bayonne,  N.  J.     15  orders,  2,246  H.P. 


^ 


95 


HEATING  LIQUIDS  AND  BOILING  BY  STEAM. 

{a.)  Efficiency  of  surface,  where  all  the  air  is 
expelled.  For  vertical  surface,  each  square 
foot  will  transmit  230  heat  units  per  hour,  for 
each  degree  of  difference  in  the  temperature 
of  the  two  sides.  For  horizontal  and  inclined 
surface,  each  square  foot  will  transmit  330  heat 
units  per  hour  for  each  degree  of  difference  in 
temperature  between  the  two  sides. 

{b.)  Steam  required.  Each  966  heat  units 
will  require  the  condensation  of  one  pound  of 
steam  at  212°   or  1,000  units  at  75  lbs.  pressure. 


iHSi3-W 


416  H.  P.  Babcock  &  Wilcox  Boilers  in  Ponce  de  Leon  Hotel,  St.  Augustine,  Fla. 


ture  by  heated  air  rests  upon  the  fact  that  the  ca- 
pacity of  air  for  moisture  is  rapidly  increased  by 
rise  in  temperature.  If  air  at  52°  is  heated  to  72°, 
its  capacity  for  moisture  is  doubled,  and  is  foui 
times  what  it  was  at  32°.  The  following  table 
gives  the  weight  of  a  saturated  mixture  of  air  and 
aqueous  vapor  at  different  temperatures  up  to 
160°  —  the  practical  limit  of  heating  air  by  steam, 
together  with  the  weight  of  vapor,  in  pounds 
and  percentage,  and  total  heat,  the  portion 
contained  in  the  vapor  and  the  quantity  of 
air  required  per  pound  of  water. 

By  the  inspection 
of  this  table  it  will  be 
seen  why  it  is  more 
economical  to  dry  at 
the  higher  tempera- 
tures. The  atmos- 
phere is  seldom  satu- 
rated with  moisture, 
and  in  practice  it  w  ill 
be  found  generally 
necessary  to  heat  the 
air  about  30°  above 
the  temperature  of 
saturation.  The  best 
effect  is  produced 
where  there  is  artifi- 
cial ventilation,  by 
fan  or  by  chimney, 
and  the  course  of  the 
heated  air  is  from 
above  downwards. 


Each  pound  of  steam  condensed  will  evaporate 
one  pound  of  water  (nearly)  from  the  tempera- 
ture of  evaporation.  Each  horse-power  of  boiler 
will  heat  30,000  lbs.  water  1°  per  hour,  or  evapo- 
rate 30  lbs.  water  in  the  same  time. 


SATURATED  MIXTURES  OF  AIR  AND  AQUEOUS  VAPOR. 


DRYING  BY  STEAM. 

There  are  three  modes  of  drying  by  steam. 
I  St.  By  bringing  wet  substances  in  direct  con- 
tact with  steam-heated  surfaces,  as  by  passing 
cloth  or  paper  over  steam-heated  cylinders,  or 
clamping  veneers  between  steam-heated  plates. 
2d.  By  radiated  heat  frona  steam  pipes,  as  in 
some  lumber  kilns,  and  laundry  drying  rooms. 
3d.  By  causing  steam-heated  air  to  pass  over 
wet  surfaces,  as  in  glue  works,  etc. 

The  second  is  rarely  used  except  in  combina- 
tion with  the  third.  The  first  is  the  most  eco- 
nomical, the  second  less  so,  and  the  third  least. 
Under  favorable  circumstances,  it  may  be  esti- 
mated that  one  horse-power  of  steam  will  evap- 
orate 24  pounds  water  by  the  first  method,  20  by 
the  second,  and  15  by  the  third. 

The  philosophy  of  drying  or  evaporating  mois- 


^ 

^ 

1^ 

"o   1)    C 

^    O.S 

0 

>.'3 

>-r-. 

■  S 

B  u  ^ 

C  > 

H-S 

Lbs. 

Cubic 
feet. 

3S 

S.004 

0.034 

0.42 

42.8 

86.69 

234-4 

3080 

40 

7 

g2o 

0.041 

0.52 

59-8 

76.59 

192 

2 

2526 

4S 

7 

S34 

0.049 

0.62 

77-7 

68.98 

i.SS 

9 

2088 

=;o 

7 

7S2 

0.059 

0.76 

97-6 

66.29 

130 

4 

1714 

'<=• 

7 

68S 

0.070 

0.91 

118.3 

64.58 

loS 

S 

1326 

60 

7 

s«q 

0.082 

1.08 

140. 1 

64.31 

91 

6 

1203 

6s 

7 

S07 

0.097 

1.29 

164.9 

64.76 

76 

4 

1004 

70 

7 

42s 

0. 114 

1.49 

189.7 

66.21 

66 

0 

868 

71 

7 

342 

0.134 

1.79 

221.6 

66.74 

SS 

0 

723 

80 

7 

262 

0.156 

2.15 

253.6 

68.02 

4S 

6 

599 

«S 

7 

1 78 

0.182 

2.54 

289.7 

6g.66 

38 

4 

505 

90 

7 

loS 

0.212 

2.98 

330-2 

71.19 

.  32 

5 

427 

qs 

7 

009 

0.245 

3-50 

373-4 

72.87 

27 

6 

363 

100 

6 

924 

0.283 

4.08 

422.0 

74.58 

23 

S 

308 

los 

6 

830 

0.325 

4.76 

474-7 

76.22 

20 

0 

263 

no 

6 

741 

0-373 

S-23 

533-9 

77.88 

17 

I 

224 

"S 

6 

650 

0.426 

6.41 

599- 1 

79-  52  ■■ 

14 

6 

192 

120 

6 

SSI 

0.4^8 

7.46 

672.4 

81.14 

12 

6 

16.3 

12=; 

6 

4S4 

0-554 

8.55 

750-5 

82.62 

10 

7 

140 

130 

6 

347 

0.630 

9.90 

839-4 

84-13 

9 

I 

118 

i^S 

6 

238 

0.714 

11.44 

936-7 

85-57 

7 

7 

102 

140 

6 

131 

0.806 

1314 

1042.7 

86.89 

6 

6 

87 

MS 

6 

oiS 

0.909 

15. II 

1160.6 

88. 1 S 

5 

6 

74 

ISO 

S 

891 

" 1.022 

17-33 

1288.4 

89-39 

4 

8 

63 

ISS 

S 

754 

1. 145 

19.88 

1427.4 

90-53 

4 

0 

53 

i5o 

5 

679 

1-333 

23-47 

1638.7 

91-93 

3-3 

43 

^ 


97 


H* 


i. 


FLOW  OF  STEAM  THROUGH  PIPES. 

The  approximate  weis^ht  of  any  lluid  which 
will  flow  in  one  minute  through  any  given  pipe 
with  a  given  head  or  pressure  may  be  found  by 
the  following  formula:  — 


IV=87 


V 


D{p,-p,)  rf- 


L 


d 


in  which    fF=  weight  in  pounds   avoirdupois 

TABLE  OF  FLOW   OF  STEAM  THROUGH  PIPES. 


d  ~  diameter  in  inches,  D  =  density  or  weight 
jjer  cul)ic  foot,  />i=: the  initial  pressure,  />2=pres- 
sure  at  end  of  pipe,  and  L  =  the  length  in  feet. 
The  following  table  gives,  approximately, 
the  weight  of  steam  per  minute  which  will  flow 
from  various  initial  pressures,  with  one  pound 
loss  of  pressure  through  straight  smooth 
pipes,  each  having  a  length  of  240  times  its  own 
diameter. 


Diameter 

of  Pipe,  in  inches.         Length  of  each 

=  240  diameters. 

by  Gauge. 

K 

I 

i'/< 

2 

2^ 

3 

4 

5 

6 

8 

10             12 

15 

18 

Pounds  per 

Square  Inch. 

Weight  of  Steam  per 

Minute,  in  pour.ds,  with  one  pound  loss  of  pressure. 

I 

1. 16 

2.07 

5-7 

10.27 

15-45 

25.38 

46.85 

77-3 

"5-9 

211. 4 

341-1 

502.4 

804 

1177 

10 

1.44 

2-57 

7 

I 

12 

72 

'9-15 

31-45 

58.05 

95-8 

143-6 

262.0 

422.7 

622 

5 

996 

1458 

20 

1.70 

3.02 

8 

3 

14 

94 

22.49 

36-94 

68.20 

112. 6 

168.7 

307.8 

496.5 

731 

3 

1170 

1713 

30 

i.gi 

3-4° 

9 

4 

16 

84 

25-35 

41.63 

76.84 

126.9 

190. 1 

346-8 

559-S 

824 

1 

1318 

1930 

40 

2.10 

3-74 

ID 

3 

18 

.SI 

27.87 

45-77 

84.49 

139-5 

209.0 

381.3 

615-3 

906 

0 

1450 

2122 

50 

2.27 

4.04 

II 

2 

20 

01 

30.13 

49-48 

91-34 

150.8 

226.0 

412.2 

665.0 

979 

5 

1567 

2294 

60 

2-43 

432 

II 

9 

21 

38 

32-19 

52-87 

97.60 

161. 1 

241.5 

440- 5 

710.6 

1046 

7 

1675 

2451 

70 

■  2-57 

4-58 

12 

6 

22 

b% 

34-10 

56.00 

103-37 

170.7 

255.8 

466. 5 

752.7 

1 108 

S 

1774 

2596 

80 

2.71 

4.82 

13 

3 

23 

82 

35-87 

58.91 

108.74 

179-5 

269.0 

490.7 

791.7 

iib6 

I 

1866 

2731 

go 

2.83 

5.04 

13 

9 

24 

92 

37-52 

61.62 

"3-74 

187.8 

281.4 

513-3 

828.1 

1219 

8 

1951 

2856 

100 

2.95 

5-25 

14 

.S 

2,S 

9b 

39-07 

64.18 

118.47 

195.6 

293.1 

534-6 

862.6 

1270 

I 

2032 

2975 

IZO 

3-16 

5-63 

15 

S 

27 

8^ 

41-93 

68.87 

127.12 

209.9 

314-5 

573-7 

925.6 

1363 

3 

2181 

3193 

150 

3-45 

6.14 

17.0 

30-37 

45-72 

75.09 

138.61 

228.8 

343-0 

625.5 

1009.2 

1486.5 

2378 

3481 

For  sizes  of  pipe  below  6-inch,  the  flow  is  cal- 
culated from  the  actual  a,reSiS  of  "standard" 
pipe  of  such  nominal  diameters. 

For  horse-power,  multiply  the  figures  in  the 
table  by  2.  For  any  other  loss  of  pressure,  mul- 
tiply by  the  square  root  of  the  given  loss.  For 
any  other  length  of  pipe,  divide  24.0  by  the  given 
length  expressed  in  diameters,  and  multiply  the 
figures  in  the  table  by  the  square  root  of  this 
quotient,  which  will  give  the  flow  for  i  lb.  loss  of 
pressure.  Conversely,  dividing  the  given  length 
by  240  will  give  the  loss  of  pressure  for  the  flow 
given  in  the  table. 

The  loss  of  head  due  to  getting  up  the  velocity, 
to  the  friction  of  the  steam  entering  the  pipe,  and 
passing  elbows  and  valves,  will  reduce  the  flow 
given  in  the  tables.  The  resistance  at  the  open- 
ing, and  that  at  a  globe  valve,  are  each  about  the 
same  as  that  for  a  length  of  pipe  equal  to  1 14 
diameters  divided  by  a  number  represented  by 
I  +  (3.6  -^  diameter).  For  the  sizes  of  pipes 
given  in  the  table,  these  corresponding  lengths 
are:  — 

_3^    I    I       I    llA    I   2       I    2V.    I     3      I     4     I     5      I     6     I     8     I    10    I    12    I    IS    I    18 

20  I  25  I  34  I  41  I  47  I  52  I  60  I  66  I  71  I  79  I  84  I  88  I  92  I  95 

The  resistance  at  an  elbow  is  equal  to  %  that 
of  a  globe  valve.  These  equivalents  — ■  for  open- 
ing, for  elbows,  and  for  valves — must  be  added 
in  each  instance  to  the  actual  length  of  pipe. 
Thus  a  4  in.  pipe,  120  diameter  (40  feet)  long, 
with  a  globe  valve  and  three  elbows,  would  be 
equivalent  to  120  +  60  +  60  +  (3  X  40)  ^  360 
diameters  long;  and  360-^  240=  i^.  It  would 
therefore  have  1%  lbs.  loss  of  pressure  at  the 


flow  given  in  the  table,  or  deliver  {i  -^  V  ij4 
=  .816)  81.6  per  cent,  of  the  steam  with  the  same 
(i  lb.)  loss  of  pressure. 


FLOW  OF  STEAM  FROM  A  GIVEN  ORIFICE. 

Steam  of  any  pressure  flowing  through  an 
opening  into  any  other  pressure,  less  than  three- 
fifths  of  the  initial,  has  practically  a  constant 
velocity,  888  feet  per  second,  or  a  little  over  ten 
miles  per  minute;  hence  the  amount  discharged 
in  pounds  is  proportionate  to  the  weight  or  den- 
sity of  the  steam.  To  ascertain  the  pounds, 
avoirdupois,  discharged  per  minute,  multiply 
the  area  of  opening  in  inches,  by  jjo  times  the 
weight  per  cubic  foot  of  the  steam.    (See  p.  73- ) 

Or  the  quantity  discharged  per  minute  may 
be  approximately  found  by  Rankine's  formula: 

W=  Gap  —  '] 
in  which  ^^=  weight  in  pounds,  a  =  area  in 
square  inches,  and  p  =  absolute  pressure.  The 
theoretical  flow  requires  to  be  multiplied  by 
k  =:  0.93,  for  a  short  pipe,  or  0.63  for  a  thin 
opening,  as  in  a  plate,  or  a  safety  valve. 

Where  the  steam  flows  into  a  pressure  more 
than  %  the  pressure  in  the  boiler: — - 
W=i.()  ak  V  {p  —  h)h 
in  which  8  =  difference  in  pressure  between  the 
two  sides,  in  pounds  per  square  inch,  and  a,  p, 
and  k  as  above. 

To  reduce  to  horse-power,  multiply  by  2. 

Where  a  given  horse-power  is  required  to  flow 
through  a  "given  opening,  to  determine  the  nec- 
essary difference  in  pressure:  — 

s    =^ 


VT 


H.P.^ 

14a  ^  k 


Exchange  Court  Building,  New  York.      632  H.P.  Babcock  &  Wilcox  Boilers. 


EQUATION  OF  PIPES. 

It  is  frequently  desirable  to  know  what  num- 
ber of  one-sized  pipes  will  be  equal  in  capacity 
to  another  given  pipe  for  delivery  of  steam,  air, 
or  water.  At  the  same  velocity  of  flow  two 
pipes  deliver  as  the  squares  of  their  internal 
diameters,  but  the  same  head  will  not  produce 
the  same  velocity  in  pipes  of  different  sizes  or 
lengths,  the  difference  being  usually  stated  to 
vary  as  the  square  root  of  the  fifth  power  of 
the  diameter.  The  friction  of  a  fluid  within 
itself  is  very  slight,  and  therefore  the  main 
resistance  to  flow  is  the  friction  upon  the  sides  of 
the  conduit.  This  extends  to  a  limited  distance, 
and  is,  of  course,  greater  in  proportion  to  the 
contents  of  a  small  pipe  than  of  a  large.  It  may 
be  approximated  in  a  given  pipe  by  a  constant 
multiplied  by  the  diameter,  or  the  ratio  of  flow 
found  by  dividing  some  power  of  the  diameter 
by  the  diameter  increased  by  a  constant.  Care- 
ful comparison  of  a  large  number  of  experi- 
ments, by  different  investigators,  has  developed 
the  following  as  a  close  approximation  to  the 
relative  flow  in  pipes  of  different  sizes  under 
similar  conditions:  — 


WCK 


V 


d^ 


^  +  3.6 


or, 


d^ 


Vd  +  ^.e 


W  being  the  weight  of  fluid  delivered  in  a  given 
time,  and  rf being  the  internal  diameter  in  inches. 


The  diameters  of  "  standard  "  steam  and  gas 
pipe,  however,  vary  from  the  nominal  diameters, 
and  in  applying  this  rule  it  is  necessary  to  take 
the  true  measurements,  which  are  given  in  the 
following  table:  — 

TABLE  OF  STANDARD  SIZES,  STEAM  AND  GAS  PIPES. 


J3 

Diameter. 

Diameter. 

A 

Diameter. 

1— 1 

i-i 

4) 

Inter- 

Exter- 

ff 

Inter- 

Exter- 

s 

Inter- 

Exter- 

o5 

nal. 

nal. 

w 

nal. 

nal 

w 

nal. 

nal. 

/8 

•27 

40 

^% 

2.47 

2.87 

19 

8.94 

9.62 

'A 

3b 

■54 

3 

3-07 

3-5 

10 

10.02 

10.75 

->8 

49 

b7 

3H 

3-55 

4 

II 

II. 

11.75 

%. 

62 

84 

4   , 

4-°3 

4-5 

12 

12. 

12.75 

y^ 

82 

I 

05 

A'A 

4.51 

5 

13 

13-25 

14 

I 

I 

05 

I 

31 

5 

5-04 

5-56 

14 

14.25 

15 

I '4 

I 

38 

I 

66 

6 

6.06 

6.62 

!■; 

15-43 

16 

1V2 

I 

61 

I 

qo 

7 

7.02 

7.62 

16 

16.4 

17 

2 

2 

07 

2 

37 

8 

7.98 

8.62 

17 

17-32 

18 

The  table  below  gives  the  number  of  pipes  of 
one  size  required  to  equal  in  delivery  other  larger 
pipes  of  same  length  and  under  same  conditions. 
The  upper  portion  above  the  diagonal  line  of 
blanks  pertains  to  ' '  standard ' '  steam  and  gas 
pipes,  while  the  lower  portion  is  for  pipes  of  the 
actual  internal  diameters  given.  The  figures 
given  in  the  table  opposite  the  intersection  of  any 
two  sizes  is  the  number  of  the  smaller  sized 
pipes  required  to  equal  one  of  the  larger.  Thus, 
it  requires  29  standard  2  inch  pipes  to  equal  one 
standard  7  inch  pipe. 


TABLE  OF  EQUATION   OF  PIPES.— STANDARD   STEAM   AND   GAS   PIPES. 


5 

% 

Ya 

^ 

iK 

2 

254 

3 

4 

5 

6 

7 

8 

9 

10 

II 

12 

13 

14 

15 

16 

17 

.2 

V. 

2.27 

4.88 

15.8 

31-7 

52-9 

96-9 

205 

377 

620 

gi8 

1,292 

1,767 

2,488 

3,014 

3,786 

4,904 

5,927 

7,321 

8,535 

9,717 

%. 

% 

2.60 

2.05 

6.97 

14.0 

23 

3 

42.  s 

90.4 

166 

273 

405 

569 

779 

1,096 

1,328 

1,668 

2,161 

2,6is 

3,226 

3,7bi 

4,282 

H 

I 

7-55 

2.90 

3-45 

6.82 

II 

4 

20.9 

44-1 

81. 1 

133 

198 

278 

380 

536 

649 

815 

1,070 

1,263 

',576 

',837 

2,092 

I 

^'A 

24.2 

9- 30 

3.20 

1.26 

3 

34 

6.13 

13.0 

23.8 

39-2 

58.1 

81.7 

12 

157 

190 

239 

3'o 

375 

463 

539 

614 

''/2 

2 

54-8 

21.0 

7-25 

2,26 

I 

67 

3.06 

6.47 

II. 9 

19.6 

29 

0 

40 

8 

55 

8 

78-5 

95.1 

Ilq 

155 

187 

231 

269 

307 

2 

2V2 

102 

39-4 

13.6, 

4-23 

1.87 

1-83 

3-87 

7.12 

II. 7 

'7 

4 

24 

4 

33 

4 

47 

0 

56.9 

7'-5 

92.6 

112 

'38 

161 

184 

2%. 

3 

170 

bS-4 

22.6 

7-03 

3-11 

I 

66 

2.12 

3-89 

6-39 

9 

48 

•3 

3 

20 

9 

23 

7 

31-2 

39-1 

50 

6 

61. 1 

75-5 

88.0 

100 

i 

4 

376 

144 

49-8 

'5-5 

6.87 

3 

67 

2.21 

1.84 

3.02 

4 

48 

6 

30 

8 

61 

12 

I 

'4-7 

18.5 

23 

9 

28.9 

35-7 

41.6 

47-4 

4 

S 

686 

263 

90.9 

28.3 

12.5 

6 

70 

4-03 

1-83 

1.6S 

2 

44 

3 

43 

6q 

6 

60 

8.00 

lo.o 

13 

0 

'5-7 

'9-4 

22.6 

25-8 

5 

6 

1,116 

429 

148 

46.0 

20.4 

lo 

9 

6.56 

2.97 

1.63 

I 

48 

09 

85 

4 

02 

4.86 

6.11 

9' 

9-56 

II. 8 

13-8 

15-6 

6 

7 

1,707 

656 

226 

70-5 

31.2 

16 

6 

lO.O 

4-54 

2-49 

1-5' 

I 

4' 

93 

2 

7' 

3-28 

4.12 

34 

6-45 

7-97 

9-31 

10.6 

7 

8 

2,435 

936 

322 

lOI 

44-5 

23 

8 

14-3 

6.48 

3-54 

2.18 

I 

43 

35 

I 

93 

2-33 

2.92 

3 

79 

4-57 

5-67 

6.60 

7-52 

8 

9 

3,335 

1,281 

440 

•37 

60.8 

32 

5 

■9-5 

8-85 

4-85 

2.98 

I 

95 

I 

37 

I 

41 

1. 71 

2.14 

2 

77 

3-35 

4.14 

4-83 

5-50 

9 

lO 

4,393 

1,688 

582 

181 

80.4 

42 

9 

25.8 

11.7 

6.40 

3-93 

2 

57 

I 

80 

32 

1. 21 

I. 52 

97 

2.38 

2.94 

3-43 

3-91 

10 

II 

5,642 

2,168 

747 

233 

103 

55 

I 

33-1 

IS-O 

8.22 

5-oS 

3 

31 

2 

32 

70 

I 

28 

1.26 

63 

1.88 

2-43 

2-83 

3-22 

II 

12 

7,087 

2,723 

938 

293 

129 

69 

2 

41.6 

18.8 

10.3 

6-34 

4 

'5 

2 

91 

2 

13 

I 

61 

1.26 

30 

1-57 

1-93 

2.26 

2.58 

12 

13 

8,657 

3,326 

1,146 

3S8 

158 

84 

s 

50.7 

23.0 

12.6 

7-75 

5 

07 

3 

56 

2 

60 

I 

98 

1-53 

1.22 

1. 21 

1.49 

1.74 

1.98 

13 

14 

10,600 

4,070 

1,403 

438 

193 

03 

62.2 

28.2 

•5-4 

9-48 

6 

21 

4 

35 

3 

18 

2 

4' 

1.88 

1.50 

22 

1.24 

1-44 

1.64 

14 

IS 

12,824 

4,927 

1,698 

530 

234 

25 

75-3 

34-1 

.8.7 

II. 5 

7 

52 

5 

27 

3 

85 

2 

92 

2.27 

1.81 

48 

1. 21 

1.17 

1-3  5 

'5 

16 

14,978 

5,758 

1,984 

6.9 

274 

46 

88.0 

39-9 

21.8 

'3-4 

8 

78 

6 

15 

4 

51 

3 

4' 

2.66 

2.  12 

73 

1.42 

1. 18 

1. 14 

16 

17 

17,537 

6,738 

2,322 

724 

320 

171 

103 

46.6 

25-6 

'5-7 

10 

3 

7 

20 

5 

27 

3 

99 

3-II 

2.47 

2 

03 

1.66 

1-37 

1.17 

18 

20,327 

7,810 

2,691 

840 

371 

198 

119 

54-1 

29.6 

18.2 

II 

9 

8 

3  5 

6 

II 

4 

63 

3.60 

2.87 

3  5 

1.92 

1-59 

1-36 

1. 16 

20 

26,676 

10,249 

3,532 

1,102 

487 

260 

157 

70.9 

38.9 

23-9 

'5 

6 

10 

9 

8 

02 

6 

07 

4-73 

3-76 

3 

08 

2.52 

2.08 

1.78 

1.52 

24 

42,624 

ib,37b 

5,644 

1,761 

778 

416 

250 

"3 

62.1 

38.2 

25 

0 

17 

5 

12 

8 

9 

70 

7-55 

6.01 

4 

92 

4.02 

3-32 

2.84 

2.43 

30 

75,453 

28,990 

9,990 

3, "7 

1,37s 

73b 

443 

201 

no 

67.6 

44 

2 

3' 

0 

22 

7 

'7 

2 

'3-4 

10.7 

8 

72 

7.14 

5.88 

5-03 

4-30 

3S 

120,100 

46,143 

15,902 

4,961 

2,193 

1,172 

705 

3 '9 

175 

108 

70 

4 

49 

3 

36 

I 

27 

3 

21-3 

16.9 

13 

9 

"-3 

9-37 

8.01 

6-85 

42 

177,724 

68,282 

23,531 

7,341 

3,245 

1,734 

1,044 

473 

259 

159 

104 

73 

0 

53 

4 

40 

5 

31-5 

25-1 

20 

5 

16.8 

'3-9 

II. 9 

10. 1 

48 

249,35' 

95,818 

33,020 

10,301 

4,554 

2,434 

1,465 

663 

363 

223 

146 

102 

75 

0 

56 

8 

44-2 

35-2 

288 

23-5 

19.4 

16.6 

14.2 

S 

'A 

K 

' 

•K 

2 

2^ 

3 

4 

5 

6 

7 

8 

9 

10 

II 

12 

13 

'4 

15 

16 

17 

ACTUAL   INTERNAL  DIAMETERS. 


^ 


101 


-^ 


>--f 


Manhattan   Hotel,  New  York.     1300  H.P.   Babcock  &  Wilcox   Boilers. 


>44. 


COVERING  FOR  BOILERS,  STEAM  PIPES,  ETC. 

The  loss  by  radiation  from  unclothed  pipes 
and  vessels  containing  steam  is  considerable, 
and,  in  the  case  of  pipes  leading  to  steam 
engines,  is  magnified  by  the  action  of  the 
condensed  water  in  the  cylinder.  It  therefore 
is  important  that  such  pipes  should  be  well 
protected. 

There  is  a  wide  difference  in  the  value  of  dif- 
ferent substances  for  protection  from  radiation, 
their  value  varying  nearly  in  the  inverse  ratio  of 


their  conducting  power  for  heat,  up  to  their  ability 
to  transmit  as  much  heat  as  the  surface  of  the 
pipe  will  radiate,  after  which  they  become  detri- 
mental, rather  than  useful,  as  covering.  This 
point  is  reached  nearly  at  baked  clay  or  brick. 
The  following  table  of  the  relative  value  of 
various  substances  for  protection  against  radia- 
tion has  been  compiled  from  a  variety  of  sources, 
mainly  the  experiments  of  the  Massachusetts 
Institute  of  Technology,  and  of  C.  E.  Emery, 
M.E.,  LL.D. 


TABLE  OF   RELATIVE  VALUE  OF   NON-CONDUCTING   MATERIALS. 


Substance. 


,  *Loose  Wool, 

*Loose  Lampblack,    .     .     .     . 

*Geese  Feathers, 

*Felt,  Hair  or  Wool, .     .     .     . 

*Carded  Cotton, 

*Charcoal  from  Cork,      .     .     . 

Mineral  Wool, 

Fossil  Meal, 

*Straw  Rope,  wound  spirally, 
*Rice  Chaff,  loose 

Carbonate  Magnesia,  .  .  . 
*Charcoal  from  Wood,    .     .     . 


Value. 


3-35 

I. 12 


.68  to  .83 
.66  to  .79 
•77 
.76 
.67  to  .76 
.63  to  .75 


Substance. 


Value. 


*Paper, 

*Cork, 

*Sawdust, 

Paste  of  Fossil  Meal  and 
Hair 

Wood  Ashes, 

*Wood,  across  grain,     .     .     . 

Loam,  dry  and  open,    .     .     . 

Chalk,  ground,  Spanish  white, 

Coal  Ashes, 

Gas-house  Carbon,  .... 

Asbestos  Paper,        .... 


.50  to  .74 

■71 

.61  to  .68 

■63 

.61 
.40  to  .55 
•55 
•51 
•35  to  .49 
■47 
•47 


Substance. 

Paste  of  Fossil  Meal  and 

Asbestos,  .... 
Asbestos,  fibrous,  .  .  . 
Plaster  of  Paris,  dry,  .  . 
Clay,  with  vegetable  fiber. 
Anthracite  Coal,  powdered. 
Coke,  in  lumps,  .... 
Air  Space,  undivided,   . 

Sand, 

Baked  Clay,  Brick,  .     .     . 

Glass, 

Stone, 


*  Combustible,  and  sometimes  dangerous. 


Where  two  values  are  given  in  the  table  for 
the  same  substance  the  lower  one  is  for  the 
denser  condition. 

A  smooth  or  polished  surface  is  of  itself  a  good 
protection,  polished  tin  or  Russia  iron  having  a 
ratio,  for  radiation,  of  53  to  100  for  cast  iron. 
Mere  color  makes  but  little  difference. 

Hair  or  wool  felt,  and  most  of  the  better  non- 
conductors, have  the  disadvantage  of  becoming 
soon  charred  from  the  heat  of  steam  at  high 
pressure,  and  sometimes  of  taking  fire  there- 
from. 

"Mineral  wool,"  a  fibrous  material  made  from 
blast  furnace  slag,  is  the  best  non-combustible 
covering,  but  is  quite  brittle,  and  liable  to  fall  to 
powder  where  much  jarring  exists. 


Air  space  alone  is  one  of  the  poorest  of  non- 
conductors, though  the  best  owe  their  efficiency 
to  the  numerous  minute  air  cells  in  their  struc- 
ture. This  is  best  seen  in  the  value  of  different 
forms  of  carbon,  from  cork  charcoal  to  anthra- 
cite dust,  the  former  being  three  times  as  valua- 
ble for  this  purpose,  though  in  chemical  consti- 
tution they  are  practically  identical. 

Any  suitable  substance  used  to  prevent  the 
escape  of  steam  heat  should  not  be  less  than 
one  inch  thick. 

The  following  table  gives  the  loss  of  heat  from 
steam  pipes,  naked  and  clothed  with  wool  or 
hair  felt,  of  different  thickness,  the  steam  pres- 
sure being  assumed  at  75  lbs.  and  the  external 
air  at  60°. 


TABLE  OF  LOSS  OF  HEAT  FROM  STEAM   FIFES. 


Outside  Diameter  of  P: 

PE,  WITHOUT  Felt. 

Thick- 

2  inch  diameter. 

4  inch  diameter. 

6  inch  diameter. 

8  inch  diameter. 

12  inch  diameter. 

in 

m 

—  <J 

w 

t/5 

-^  ^ 

<Si                   1 

X.  ^ 

fSi 

• 

^     • 

tn 

J=  <-• 

of 

Covering, 

in 

inches. 

0 

Mo 

5    . 

1-1  Ph 

•Sffi 

0 

0 
0 

0 

"o 
0 

•SS 

m 

0 

h-1 

'0 
0 

tjp.; 
•Sk 

0 

'0 
0 

si;^ 

t;  V- 

i^^ 

OJ       ^H 

isS. 

'S  s 

0  s  t^ 

"oj    1-. 

S  fc  a 

hJ  ^ 

A 

fc  0. 

J  ^ 

lA 

fe       f^ 

J  o- 

Pi 

fe,  a 

J  ^ 

Pi 

cS  0- 

hJ    ^ 

Pi 

fo  s. 

0 

219.0 

1. 00 

152 

390.8    I 

00 

86 

624.1 

1. 000 

53 

729.8 

1.000 

46 

1077.4 

1. 000 

31 

^ 

100.7 

.46 

331 

180.9 

46 

182 

% 

65.7 

•30 

507 

117. 2 

30 

284 

187.2 

.300 

177 

219.6 

.301 

151 

301.7 

.280 

114 

I 

43-8 

.20 

761 

73^9 

18 

451 

III.O 

.178 

300 

128.3 

.176 

259 

185.3 

.172 

179 

2 

28.4 

•13 

"73 

44-7 

II 

745 

66.2 

.106 

504 

75-2 

.103 

443 

98.0 

.091 

340 

4 

19.8 

.09 

1683 

28.1 

07 

1 186 

44.2 

.066 

808 

46.0 

.063 

724 

60.3 

.056 

553 

6 

23-4 

06 

1424 

33-7 

•  054 

989 

34-3 

.047 

972 

45.2 

.042 

735 

>-"♦■ 


103 


^< 


Bank  of  Commerce  Building  and  New  York  Clearing  House,  containing  respectively  566  H.P,  and  118  H.P. 

Babcock  &  Wilcox  Boilers. 


•^ 


CARE  OF  BOILERS. 

The  following  rules  are  compiled  from  those 
issued  by  various  Boiler  Insurance  Companies 
in  this  country  and  Europe,  supplemented  by 
our  own  experience.  They  are  applicable  to  all 
boilers,  except  as  otherwise  noted. 

ATTENTION  NECESSARY  TO  SECURE  SAFETY. 

[Though  the  Babcock  &  Wilcox  boilers  are 
not  liable  to  destructive  explosion,  the  same  care 
should  be  exercised  to  avoid  possible  damage 
to  boiler,  and  expensive  delays.] 

1.  Safety  Valves.^— Great  care  should  be 
exercised  to  see  that  these  valves  are  ample  in 
size  and  in  working  order.  Overloading  or 
neglect  frequently  leads  to  the  most  disastrous 
results.  Safety  valves  should  be  tried  at  least 
once  every  day  to  see  that  they  will  act  freely. 

2.  Pressure  Gauge. — The  steam  gauge 
should  stand  at  zero  when  the  pressure  is  off, 
and  it  should  show  the  same  pressure  as  the 
safety  valve  when  that  is  blowing  off.  If  not, 
then  one  is  wrong,  and  the  gauge  should  be 
tested  by  one  known  to  be  correct. 


3.  Water  Level.— The  first  duty  of  an  en- 
gineer before  starting,  or  at  the  beginning  of 
his  watch,  is  to  see  that  the  water  is  at  the  proper 
height.  Do  not  rely  on  glass  gauges,  floats  or 
water  alarms,  but  try  the  gauge  cocks.  If  they 
do  not  agree  with  water  gauge,  learn  the  cause 
and  correct  it.  Water  level  in  Babcock  &  Wil- 
cox boilers  should  be  at  center  of  drum,  which 
is  usually  at  middle  gauge.  It  should  not  be 
carried  above. 

4.  Gauge  Cocks  and  Water  Gauges 
must  be  kept  clean.  Water  gauge  should  be 
blown  out  frequently,  and  the  glasses  and  pas- 
sages to  gauge  kept  clean.  The  Manchester, 
Eng.,  Boiler  Association  attribute  more  acci- 
dents to  inattention  to  water  gauges  than  to  all 
other  causes  put  together. 

5.  Feed  Pump  or  Injector.  —  These 
should  be  kept  in  perfect  order,  and  be  of  ample 
size.  No  make  of  pump  can  be  expected  to  be 
continuously  reliable  without  regular  and  care- 
ful attention.  It  is  always  safe  to  have  two 
means  of  feeding  a  boiler.  Check  valves  and 
self-acting    feed    valves    should  be  frequently 


» <%•* 


Tube  Shed. 


105 


•^ 


examined  and  cleaned.  Satisfy  yourself  fre- 
quently that  the  valve  is  acting  when  the*  feed 
pump  is  at  work. 

6.  Low  Water. — In  case  of  low  water,  im- 
mediately cover  the  fire  with  ashes  (wet  if  pos- 
sible) or  any  earth  that  may  be  at  hand.  If 
nothing  else  is  handy  use  fresh  coal.  Draw  fire 
as  soon  as  it  can  be  done  without  increasing  the 
heat.  Neither  turn  on  the  feed,  start  or  stop 
engine,  nor  lift  safety  valve  until  fires  are  out, 
and  the  boiler  cooled  down. 

7.  Blisters  and  Cracks. — These  are  liable 
to  occur  in  the  best  plate  iron.  When  the  first 
indication  appears  there  must  be  no  delay  in  hav- 
ing it  carefully  examined  and  properly  cared  for. 


serious  waste  of  fuel.  The  frequency  of  cleaning 
will  depend  on  the  nature  of  fuel  and  water. 
As  a  rule,  never  allow  over  -^^  inch  scale  or  soot 
to  collect  on  surfaces  between  cleanings.  Hand- 
holes  should  be  frequently  removed  and  surfaces 
examined,  particularly  in  case  of  a  new  boiler, 
until  proper  intervals  have  been  established  by 
experience. 

The  Babcock  &  Wilcox  boiler  is  provided  with 
extra  facilities  for  cleaning,  and  with  a  little  care 
can  be  kept  up  to  its  maximum  efficiency,  where 
tubulars  or  locomotive  boilers  would  be  quickly 
destroyed.  For  inspection,  remove  the  hand- 
holes  at  both  ends  of  the  tubes,  and  by  holding 
a  lamp  at  one  end  and  looking  in  at  the  other, 


-6-2^ <] 

I 


1.H  SAFETY  VALVE 
7-1^ — 


«Q,.^ n n 


25  H.P,  Boiler  built  to  carry  300  to  400  lbs.  pressure  for  Nikola  Tesla,  New  York. 


8.  Fusible  Plugs,  when  used,  must  be 
examined  when  the  boiler  is  cleaned,  and 
carefully  scraped  clean  on  both  the  water  and 
fire  sides,  or  they  are  liable  not  to  act. 

ATTENTION  NECESSARY  TO  SECURE  ECONOMY. 

9.  Firing. — Fire  evenly  and  regularly,  a 
little  at  a  time.  Moderately  thick  fires  are  most 
economical,  but  thin  firing  must  be  used  where 
the  draught  is  poor.  Take  care  to  keep  grates 
evenly  covered,  and  allow  no  air-holes  in  the 
fire.  Do  not  "  clean  "  fires  oftener  than  neces- 
sary. With  bituminous  coal,  a  "coking  fire," 
t.  e.,  firing  in  front  and  shoving  back  when 
coked,  gives  best  results,  if  properly  managed. 

10.  Cleaning. — All  heating  surfaces  must  be 
kept  clean  outside  and  in,  or  there  will  be  a 


the  condition  of  the  surface  can  be  fully  seen. 
Push  the  scraper  through  the  tube  to  remove 
sediment,  or  if  the  scale  is  hard  use  the  chipping 
scraper  made  for  that  purpose.  Water  through 
a  hose  will  facilitate  the  operation.  In  replacing 
hand-hole  caps,  clean  the  surfaces  without 
scratching  or  bruising,  smear  with  oil,  and 
screw  up  tight.  Examine  mud-drum  and  remove 
the  sediment  therefrom. 

The  exterior  of  tubes  can  be  kept  clean  by 
the  use  of  blowing  pipe  and  hose  through  open- 
ings provided  for  that  purpose.  In  using  smoky 
fuel,  it  is  best  to  occasionally  brush  the  surfaces 
when  steam  is  of?. 

11.  Hot  Feed-Water. — Cold  water  should 
never  be  fed  into  any  boiler  when  it  can  be  avoid- 
ed, but  when  necessary  it  should  be  caused  to 


►it 


106 


■►-< 


mix  with  th;^  heated  water  before  coming  in  con- 
tact with  any  portion  of  the  boiler. 

12.  Foaming. — When  foaming  occurs  in  a 
boiler,  checking  the  outflow  of  steam  will  usually 
stop  it.  If  caused  by  dirty  water,  blowing  down 
and  pumping  up  will  generally  cure  it.  In  cases 
of  violent  foaming,  check  the  draft  and  fires. 

Babcock  Sz  Wilcox  boilers  never  foam  with 
good  water,  unless  the  water  is  carried  too  high. 
If  found  to  prime,  lower  the  water  line.  It 
should  not  be  carried  above  center  line  of  drum. 

13.  Air  Leaks. — Be  sure  that  all  openings 
for  admission  of  air  to  boiler  or  flues,  except 
through  the  fire,  are  carefully  stopped.  This  is 
frequently  an  unsuspected  cause  of  serious 
waste. 

14.  Blowing  Off.— If  feed-water  is  muddy 
or  salt,  blow  off  a  portion  frequently,  according 
to  condition  of  water.  Empty  the  boiler  every 
week  or  two,  and  fill  up  afresh.  When  surface 
blow-cocks  are  used,  they  should  be  often 
opened  for  a  few  minutes  at  a  time.  Make  sure 
no  water  is  escaping  from  the  blow-off  cock 
when  it  is  supposed  to  be  closed.  Blow-off 
cocks  and  check-valves  should  be  examined 
every  time  the  boiler  is  cleaned. 

Attention  Necessary  to  Secure  Durability. 

15.  Leaks. — When  leaks  are  discovered, 
they  should  be  repaired  as  soon  as  possible. 

16.  Blowing  Off. — Never  empty  the  boiler 
while  the  brickwork  is  hot. 


17.  Filling  Up. — Never  pump  cold  water 
into  a  hot  boiler.  Many  times  leaks,  and,  in 
shell  boilers,  serious  weaknesses,  and  sometimes 
explosions  are  the  result  of  such  an  action. 

18.  Dampness. — Take  care  that  no  water 
comes  in  contact  with  the  exterior  of  the  boiler 
from  any  cause,  as  it  tends  to  corrode  and 
weaken  the  boiler.  Beware  of  all  dampness  in 
seatings  or  coverings. 

19.  Galvanic  Action. — Examine  frequently 
parts  in  contact  with  copper  or  brass,  where 
water  is  present,  for  signs  of  corrosion.  If 
water  is  salt  or  acid,  some  metallic  zinc  placed 
in  the  boiler  will  usually  prevent  corrosion,  but 
it  will  need  attention  and  renewal  from  time  to 
time. 

20.  Rapid  Firing. — In  boilers  with  thick 
plates  or  seams  exposed  to  the  fire,  steam  should 
be  raised  slowly,  and  rapid  or  intense  firing 
avoided.  With  thin  water  tubes,  however,  and 
adequate  water  circulation,  no  damage  can 
come  from  that  cause. 

21.  Standing  Unused. — If  a  boiler  is  not 
required  for  some  time,  empty  and  dry  it  thor- 
oughly. If  this  is  impracticable,  fill  it  quite  full 
of  water,  and  put  in  a  quantity  of  common 
washing  soda.  External  parts  exposed  to  damp- 
ness should  receive  a  coating  of  linseed  oil. 

22.  General  Cleanliness.  — All  things 
about  the  boiler  room  should  be  kept  clean  and 
in  good  order.  Negligence  tends  to  waste  and 
decay. 


107 


■^ 


►  -^ 


TE5T5  'of  the^.l 


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W 


i-i^-^iv-^ 


\m 


BOILEKS 


TESTING   STEAM  BOILERS. 

The  object  of  testing  a  steam  boiler  is  to 
determine  the  quantity  and  quality  of  steam  it 
will  supply  continuously  and  regularly,  under 
specified  conditions;  the  amount  of  fuel  re- 
quired to  produce  that  amount  of  steam,  and 
sometimes  sundry  other  facts  and  values.  In 
order  to  ascertain  these  things  by  observation 
it  is  necessary  to  exercise  great  care  and  skill, 
and  employ  the  most  perfect  apparatus,  or 
errors  will  creep  in  sufficient  to  vitiate  the  test 
and  render  it  of  no  value,  if  not  actually  mis- 
leading. This  is  most  apparent  in  testing  the 
quality  of  the  steam  by  a  "  barrel  calorimeter ' ' 
as  at  the  Centennial  Exposition,  where  an  error 
of  %  pound  in  either  of  two  weighings  of  a  mass 
of  some  400  pounds  made  a  difference  of  3  %  in 
the  final  result. 

The  principal  points  to  be  ascertained  and 
noted  in  a  boiler  test  are: — 

1.  The  type  and  dimensions  of  the  boiler, 
including  the  area  of  heating  surface,  steam  and 
water  space,  area  of  water  surface,  and  draft 
area  through  or  between  tubes  or  flues. 

2.  The  kind  and  size  of  furnace;  area  of  grate 
with  proportion  of  air  spaces  therein,  height  and 
size  of  chimney,  length  and  area  of  flues  or  tubes. 

3.  Kind  and  quality  of  fuel,  if  coal  from  what 
mine,  etc. ;  percentage  of  refuse,  and  percentage 
of  moisture.  The  latter  is  a  more  important 
item  than  is  generally  understood,  as  in  adding 
directly  to  the  weight  it  introduces  an  error  in 
the  final  results  directly  proportioned  to  the  per 
cent,  of  the  fuel. 

4.  Temperature  of  feed-water  entering  boiler 
and  temperature  of  flue  gases.  The  tempera- 
tures of  fire-room  and  of  external  air  may  be 
noted,  but  are  usually  of  slight  importance. 

5.  Pressure  of  steam  in  boiler,  draft  pressure 
in  furnace  at  boiler  side  of  damper  in  flue  con- 
nection with  breeching  or  stack,  and  the  blast, 
if  any,  in  the  ash  pit. 

6.  Weights  of  feed-water,  of  fuel,  and  of  ashes. 
Water  meters  are  not  reliable  as  an  accurate 
measure  of  feed-water. 

7.  Time  of  starting  and  of  stopping  test,  taking 


care  that  the  observed  conditions  are  the  same 
at  each,  as  far  as  possible. 

8.  The  quality  of  the  steam,  whether  "  wet," 
"dry,"  or  superheated. 

From  these  data  all  the  results  can  be  figured, 
giving  the  economy  and  capacity  of  the  boiler, 
and  the  sufficiency  or  insufficiency  of  the  condi- 
tions, for  obtaining  the  best  results. 

For  purposes  of  comparison  with  other  tests, 
the  water  actually  evaporated  under  the  ob- 
served conditions  per  pound  of  coal  and  com- 
bustible and  per  square  foot  of  heating  surface 
per  hour  are  reduced  to  what  is  called  "Equiva- 
lent Evaporation"  from  and  at  212°.  In  other 
words,  the  results  are  reduced  to  certain  stand- 
ard conditions  for  all  tests,  namely  :  Pressure 
equal  to  that  of  the  atmosphere,  and  the  tem- 
perature of  the  feed-water  212°. 

These  equivalent  results  are  ascertained  by 
multiplying  the  actual  results  by  a  so-called 
"factor  of  evaporation"  which  is  found  by 
means  of  the  formula: — 

H—h 


Factor  of  evaporation  = 
in  which  H- 


965-8 
total  heat  above  32°  in  steam  at 
boiler  pressure  ;  h  =  total  heat  above  32°  in  i 
pound  of  feed-water  (see  table,  page  73);  965.8 
=  latent  heat  of  steam  at  atmospheric  pressure. 

The  standard  boiler  horse-power,  30  pounds 
water  evaporated  per  hour  from  a  temperature 
of  100°  to  steam  at  70  pounds  pressure,  is  equal 
to  about  2)A%  pounds  from  and  at  212°. 

For  further  information  concerning  the  mak- 
ing of  boiler  tests,  see  Transactions  of  the 
American  Society  of  Mechanical  Engineers, 
Vol.  VI.,  pages  256-357. 


Engineering  Office  of  Chas.  E.  Emery, 
No.  7  Warren  Street,  New  York, 
March  21,  1879. 
Messrs.  Babcock  &  Wilcox, 

No.  30  Cortlandt  Street,  New  York. 
Gentlemen:  On  the  4th  and  5th  of  Febru- 
ary, 1879,  I  made  a  trial  of  the  Babcock  &  Wil- 
cox Boilers  and  Corliss  engines  in  the  Raritan 
Woolen  Mills,  Raritan,  N.  J.,  the  results  of 
which  are  shown  in  the  following  report:  — 


"i^ 


109 


I 


^^ 


•^M 


There  were  two  boilers  tested  of  the  water- 
tube  type,  manufactured  by  you  and  known  by 
your  name,  rated  jointly  at  360  horse-power,  and 
reported  to  contain  4,080  square  feet  of  heating 
surface,  and  103  square  feet  of  grate  surface. 
These  boilers  were  erected  side  by  side  and 
connected  so  that  they  could  be  used  separately 
or  conjointly  in  connection  with  or  independent 
of  a  number  of  Lancashire  drop-flue  boilers, 
three  boilers  of  the  latter  kind  having  been  re- 
moved to  make  room  for  yours.  All  the  boilers 
were  connected  to  a  single  chimney  through  a 
Green's  economizer  in  the  fine.  A  large  por- 
tion of  the  steam  generated  appeared  to  be 
used  in  the  dye  house  and  for  heating  pur- 
poses. A  portion  of  the  boilers  were  employed, 
however,  to  supply  steam  to  two  pairs  of  en- 
gines, of  equal  size,  operating  the  mill,  one  pair 
being  of  the  Wright  patent,  put  in  many  years 
since,  and  the  other  of  Corliss  make,  erected 
within  a  year.  Each  steam  cylinder  was  20 
inches  in  diameter  with  48  inches  stroke  of 
piston.  The  engines  are  provided  with  Bulkley 
condensers.  In  the  ordinary  working  of  the 
mill  your  boilers  were  used  to  supply  steam  to 
both  pairs  of  engines. 

Your  contract  contained  a  guarantee  that  the 
boilers  should  furnish  sufficient  steam  to  de- 
velop the  rated  power  (360  H.  P. )  in  a  Corliss 
engine,  and  that  the  evaporation  should  equal 
at  least  9  pounds  of  water  from  a  temperature 
of  180°  per  pound  of  coal  containing  not  more 
than  12  per  cent,  of  refuse.  In  a  preliminary 
trial  part  of  the  load  on  the  Wright  engines 
was  transferred  to  the  Corliss  engines;  but  it 
was  soon  found  that  the  latter  did  not  require 
all  the  steam  your  boilers  would  generate  eco- 
nomically; so  two  trials  were  made,  one  of  4^^ 
hours'  duration,  using  your  boilers  with  reduced 
draft  to  supply  steam  to  the  Corliss  engines 
only,  and  taking  data  to  ascertain  the  economy 
of  the  engines;  the  other  of  fully  12  hours'  du- 
ration, using  the  boilers  at  inascintiiin  power  on 
a  dull  day  without  forcing  the  fires,  part  of  the 
steam  being  used  to  operate  the  Corliss  engines, 
the  remainder  blown  into  the  pipe  system  of 
the  other  boilers,  which  were  working  at  a 
much  less  pressure. 

Trial  of  the  Boilers. 

The  experiment  commenced  at  6.or  a.m.,  and 
closed  at  6.38  p.m.  In  starting,  steam  was 
raised  by  spreading  the  banked  fires  left  from 
the  previous  day.  When  the  pressure  reached 
80  pounds  the  fires  were  hauled,  all  refuse  re- 
moved, and  fires  started  anew  with  wood, 
which  in  calculation  has  been  considered  equal 
in  calorific  value  to  j*o  its  weight  of  coal.     The 


fires  were  maintained  with  coal  during  the  day, 
finally  hauled,  allowed  to  cool,  the  combustible 
portion  deducted  from  the  coal  charged,  and 
the  refuse  weighed  separately.  The  experi- 
ment was  closed  when  the  boilers  stopped 
making  steam  at  80  lbs.  pressure,  with  water  in 
the  glass  gauges  at  same  height  as  in  starting. 

During  the  trial,  all  the  coal  consumed  was 
weighed  in  an  iron  wheelbarrow,  balanced 
when  empty  by  a  fixed  weight,  and  each  bar- 
row load  was  adjusted  at  the  scale  to  weigh 
200  pounds  net.  All  the  water  evaporated  was 
measured  in  a  tank  provided  with  a  heavy  float 
connected  through  a  fine  chain  to  an  index 
showing  a  water  level  on  an  exterior  scale, 
divided  decimally.  By  weighing  water  out  of 
the  tank,  its  capacity  was  found  to  be  5,172 
pounds  of  water  between  the  limits  employed. 

A  complete  record  was  kept  of  the  coal,  water, 
steam  pressure  and  various  temperatures,  and  the 
quality  of  the  steam  was  tested  with  a  calorime- 
ter at  frequent  intervals.  The  proprietors  of 
the  mill  took  the  proper  business  precaution  of 
stationing  observers  at  each  point,  who  kept 
entirely  independent  records,  agreeing  with  those 
taken  by  my  assistants.  The  coal  used  was  clean 
nut  coal  from  the  Lackawanna  region.  It  had 
been  exposed  to  the  weather  during  the  winter, 
and  when  first  taken  from  the  pile  was  wet,  but 
a  sufficient  quantity  for  the  trial  was  brought 
under  shelter  a  few  days  in  advance,  so  that  the 
coal  actually  used  was  bright  and  appeared  dry. 
The  results  of  the  trial  are  as  follows  :  — 

Average  steam  pressure, 71-63 

Average  temperature  of  fire  room,       44.00 

Average  temperature  of  water  in  feed  tank,  ....  90.47 
Average  temperature  of  water  entering  boiler  after 

passing  through  a  heater  in  fiue, 110.59 

Average  temperature  of  up -take  boiler  No.  i  by 

pyrometer  (evidently  wrong), 381.87 

Average  temperature  of  flue  beyond  feed- water  heater,  453.23 

Wood  used  in  starting  fires,  730  lbs.,  equivalent 

of  coal  (730  X. 4), lbs.,       292 

Coal  put  in  furnaces  during  experiment,  .     .     lbs. ,  19,827 

Total  of  above, lbs.,  20,119 

Combustible  in  refuse  at  close  of  experimerit,  lbs.,  820 

Total  coal  consumed,  including  equivalent  of 

wood, lbs.,  191299 

Refuse  from  coal  removed  during  experiment,  lbs. ,       749 
Refuse  from  coal  at  close  of  e.xperiment,       .     lbs.,    2,134 

Total, lbs.,  2,883 

Actual  percentage  of  refuse, 

(2,883  'T'  19)299  X  100  =) 14.94 

Combustible  consumed,  (19,299  —  2,883=)     .     .    lbs.,     16,416 

Coal  with  12  per  cent,  refuse  agreed  upon,  equivalent  to 

that  actually  consumed,  [i6,4i6-j-(ioo — 12)=]  lbs.,  18,654.5 

Total  weight  of  water  actually  evaporated  at  pressure 

of  71.63  lbs.  from  temperature  110.59°,       lbs.,  161,573.28 

Equivalent  evaporation  at  pressure  of  70  lbs.  from  tem- 
perature of  180°,  as  agreed  upon,      .     .     lbs.,  172,592.58 

Evaporation 'per  lb.  of  coal,  with  12  percent,  of  refuse, 

at  pressure  of  70  lbs.  from  temperature  of  180°,       9,252 

Evaporation  per  lb.  of  combustible,  atmospheric  pres- 
sure, from  temperature  of  212°,  11,221 


111 


■* 


-^M 


Calorimeter  Trials. 

The  calorimeter  consisted  of  a  simple  barrel  set 
on  a  platform  scale.  The  scale  beam  was  grad- 
uated for  half-pounds  only  ;  but  by  applying 
thereto  an  extra  movable  weight,  one-tenth  that 
of  the  other,  carefully  leveling  the  platform,  and 
in  weighing  bringing  the  end  of  the  beam  just 
clear  of  the  guard,  it  was  possible  to  read  to 
one-tenth,  or  even  .05  of  a  pound.  In  an  in- 
clined position,  through  the  side  of  the  barrel, 
was  fixed  a  thermometer  graduated  to  %  de- 
grees, and  readily  read  to  yi  degrees.  A  small 
iron  propeller  on  a  vertical  shaft  was  arranged 
in  the  barrel.  In  operations  the  barrel  was 
nearly  filled  with  cold  water,  which  was  heated 
with  steam,  when  the  increase  in  weight  showed 
the  weight  of  steam  taken  from  the  boiler,  and 
the  increase  in  temperature  measured  the  quan- 
tity of  heat  in  the  steam.  The  steam  was  taken 
from  the  boiler  near  the  issuing  current,  through 
a  2  inch  pipe  reduced  outside  of  the  boiler  to  ^4' 
of  an  inch,  and  again  near  the  outer  end  by  an 
inserted  nipple  to  y\  of  an  inch,  substantially  on 
the  plan  recommended  in  a  previous  article  on 
the  subject.*  To  the  end  of  the  steam  pipe  a 
short  piece  of  hose  was  connected  through  a 
valve;  the  pipe  was  carefully  felted,  and  was 
heated  previous  to  each  experiment  by  wasting 
steam  through  it  before  putting  the  hose  into  the 
calorimeter.  The  end  of  the  hose  was  perforated 
in  several  directions,  to  avoid  the  jar  due  to 
condensation. 

Seventeen  experiments  were  made  during  the 
day;  one  was  rejected  in  which  the  thermometer 
scale  was  seen  to  move  by  bringing  the  hose  too 
near  the  instrument.  The  results  were  calcu- 
lated from  the  records  of  the  remaining  sixteen 
experiments,  on  the  following  basis:  — 

Let  W  =  original  weight  of  water  in  calorimeter. 

Let  ■w  =  weight  of  water  added  by  heating  with  steam. 

Let  T  =  total  heat  in  water  due  to  the  temperature  of  steam  at 

observed  pressure. 
Let  H  =  total  heat  of  steam  at  obsen^ed  pressure. 
Let    /  =  latent  heat  of  steam  at  obsen'ed  pressure. 
Let    i  =  total  heat  of  water  corresponding  to  temperature  of 

water  in  calorimeter. 
Let   i'  =  total  heat  in  water  corresponding  to  final  temperature 

of  water  in  calorimeter. 
Let  E  =  heating  efficiency  of  the  steam  furnished,  compared 

with  saturated  steam   between  the  same  limits  of 

temperature. 
Let  Q  ==  quality  of  steam  explained  hereafter. 


Then   E  =^ 


w  i^'  —  o 


(I) 


The  value  of  E  was  ascertained  by  the  formula 
separately  for  each  experiment.  The  average 
value  was  .9916,  showing  that  the  steam  lacked 
but  y\%  of  I  per  cent,  of  the  quantity  of  heat  re- 

*  Report  of  Judges,  Group  XX,  Centennial  Exhibition,  p.  82. 


quired  for  producing  perfectly  dry  or  saturated 
steam  between  the  same  limits  of  temperature. 

The  value  of  Q  may  be  found  directly  from  the 
following  equation:  — 

I  /  W 
/  \  w 


Q 


-(/^— /)  — (T  — /^ 


(2) 


or,  from  the  average  of  the  heating  efficiencies, 
by  the  following:  — 

_{H-f)    (  I  -  E  ) 


Q 


/ 


(3) 


Then  when  Q  <C  i,  the  percentage  of  moisture 
in  steam  =  100(1  — ^Q). 

When  O  >  I,  the  number  of  degrees  steam 
is  superheated  =r  2.0S33  /  (Q  —  i). 

In  the  present  case  Q  =  .98955.  Percentage 
of  moisture  in  steam  =  1.045. 

This  is  practically  dry  steam,  and  equal  in 
quality  to  that  furnished  by  boilers  of  any  type 
not  provided  with  superheating  surface.  The  ex- 
periments show,  in  a  gratifying  manner,  that  you 
have  succeeded  in  overcoming  a  great  difficulty 
often  experienced  with  boilers  constructed  of  a 
combination  of  small  chambers  to  reduce  the 
danger  of  explosion.  The  deficiency  of  ordinary 
boilers  in  furnishing  dry  steam  is  little  known, 
though  the  economy  is  materially  affected. 

Engine  Trials. 

The  preliminary  trial  of  engines  gave  the  fol- 
lowing results:  — 

Duration  of  experiment, ,     .  4.  i      hours. 

Average  steam  pressure  in  boilers,  .     .     .     .  93.94      pounds. 

Average  vacuum  in  condenser, 21.5        inches. 

Average  revolution  of  engine  per  minute,      .  64.492 

Water  evaporated  per  hour, 8830.244    pounds. 

Average  initial  pressure  in  steam  cylinders,  .  84.425    pounds. 

Mean  effective  pressure  in  cylinders,   .     .     .  30. 1275  pounds. 

Average  point  of  cut-off , .129    stroke. 

Average  indicated  H.  P.  (both  engines),   .     .  292.613 
Maximum  H.P.  shown  by  a  complete  set  of 

diagrams, 315.580 

Water  per  indicated  horse-power  per  hour,  .  30.177    pounds. 

The  steam  pipe  was  131  feet  long,  and  other 
conditions  were  unfavorable  for  the  economical 
development  of  power  in  the  engines.  It  is,  in 
fact,  popularly  supposed  that  this  class  of  engines 
develops  a  horse-power  for  %  the  quantity  of 
steam  required  in  this  case. 

The  duration  of  the  boiler  experiment  was  12 
hours  and  37  minutes,  of  which  fully  13  minutes 
were  necessarily  lost  in  starting  and  hauling  fires. 
On  this  basis  the  water  was  evaporated  in  12.4 
hours,  or  at  the  equivalent  rate  of  i3,9i9pounds 
per  hour  for  feed-water  at  180  degrees.  On  the 
basis  that  any  good  engine  under  fair  conditions 
will  require  but  30  pounds  of  water  per  horse- 
power per  hour  your  boilers,  during  this  experi- 
ment, though  not  forced  to  their  utmost,  devel- 


113 


oped  under  condition  agreed  upon,  13,919  -^  30 
=  464  horse-power,  or  104  horse-power  in  excess 
of  the  guaranteed  power. 

The  coal  recjuired  per  horse-power  per  hour  is 
evidently  dependent  in  any  case  upon  the  econ- 
omy of  the  boiler  and  engine  jointly.  With  an 
evaporation  of  9.252  pounds  of  water  per  pound 
of  coal,  and  30  pounds  of  water  per  horse-power 
in  the  engine,  there  would  be  required  per  horse- 
power per  hour  3. 24  pounds  of  coal.  This  boiler 
performance,  however,  is  rarely  obtained  in 
ordinary  practice,  so  generally  a  low  cost  of 
power  in  fuel  is  due  to  using  an  excellent  engine 
with  a  fair  boiler.  For  instance,  during  the  offi- 
cial trial  of  one  of  the  most  prominent  pumping 
engines  in  this  country,  the  boilers,  which  were 
specially  designed  to  secure  economy,  actually 
evaporated  but  8.31  pounds  of  water  at  a  pressure 
of  89. 4  pounds  from  a  temperature  100°  per  lb. 


of  Cninberland  coal  ;  yet  the  engine  was  so 
economical  that  there  was  required  but  1.69  lbs. 
of  coal  per  horse-power  per  hour.  The  equiva- 
lent evaporation  of  your  boilers  from  the  same 
temperature  with  anthracite  nut  coal,  much  in- 
ferior to  Cumberland,  on  the  basis  of  the  trial 
above  mentioned,  is  8.547  pounds  of  water  per 
pound  of  coal;  so  if  your  boilers  were  used  in 
connection  with  that  particular  pumping  engine, 
there  would  be  required  but  1.64  pounds  of  the 
inferior  coal  per  horse-power  per  hour. 

The  economical  performance  of  your  boilers 
could  undoubtedly  be  rendered  still  greater  by 
reducing  the  rate  of  evaporation.  To  accomplish 
this  result  to  the  fullest  extent,however,the  boiler 
would  probably  need  to  be  so  proportioned  that 
it  would  not  develop  a  maximum  of  464  horse- 
power, or  upward,  as  in  its  present  form. 

Very  truly  yours,  Chas.  E.  Emery. 


Babcock.  &  Wilcox  Boilers  at  the  Chelsea  Electricity  Supply  Company's  Station,  Chelsea,  Eng.      360  H.P. 
Erected  1888-9.     The  Brush  Electric  Engineering  Co.,  Limited,  London,  Contractors. 


^ 


\\l 


•¥"i 


THE   UNPARALLELED   RECORD 

Of  the  Babcock  &  Wilcox  Water-Tube  Boilers, 
as  shown  in  the  preceding  pages,  proves  once 
again,  and  particularly  in  regard  to  boilers,  what 
has  been  frequently  proved  in  regard  to  other 
things,  that  ' '  the  best  is  the  cheapest, ' '  no 
matter  what  may  be  the  first  cost. 

In  purchasing  boilers  the  buyer  wishes  to  be 
assured  on  six  points,  two  regarding  the  parties 
with  whom  he  is  dealing,  and  four  pertaining  to 
the  article  to  be  purchased.  Of  the  former  he 
wishes  to  know,  first,  if  the  party  is  financially 
responsible  and  has  such  reputation  that  he  may 
depend  upon  being  honorably  treated,  and,  sec- 
ond, if  the  manufacturer  is  likely  to  remain  long 
enough  in  business  to  supply  needed  repairs 
from  the  special  patterns  employed. 


-^tr'r! 


Il._l 


I 

Ill  I 
III  III  I 
■  p  III 
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j    I 


Front  of  a  Cross  Drum  Boiler. 

In  regard  to  the  boiler  he  needs  to  know  :  — 

I. — Its  Reliability:  Whether  it  can  be 
depended  upon  to  do  his  work  through  thick 
and  thin.  Long  and  satisfactory  use  by  different 
persons  under  various  conditions  is  the  best 
answer  to  this  question. 

2.  —  Its  Economy  :  Whether  it  will  be  waste- 
ful or  saving  in  the  use  of  fuel.  Economy  is 
claimed  in  behalf  of  every  boiler  made,  and 
many  times  to  an  extravagant  and  impossible 


extent.     Here  again  a  long  and  favorable  record 
is  the  only  certain  criterion. 

3.  —  Its  Safety  :  Whether  it  is  liable  to  ex- 
plode and  cause  a  greater  damage  to  life  and 
property  than  it,  with  all  its  other  advantages, 
is  worth.  Time  is  also  necessary  to  prove  the 
truth  of  claims  in  this  respect. 

4.  —  Its  Durability  :  Will  it  require  early  or 
extensive  repairs,  or  have  soon  to  be  replaced 
with  another  construction  ?  Nothijtg  but  a  long- 
continued  use  can  determine  this  point.  No  less 
than  thirtycompetitors  in  water-tube  boilershave 
arisen,  flourished  for  a  short  time,  and  then  sunk 
to  oblivion  since  the  Babcock  &  Wilcox  boiler 
was  first  introduced.  Of  nine  sectional  boilers 
at  the  U.  S.  Centennial,  the  Babcock  &  Wilcox 
is  the  only  one  now  manufactured,  thus  justify- 
ing the  caution  of  the  judges,  who,  in  awarding 
the  prizes,  said  that  time  alone  could  determine 
the  value  of  the  construction.  He  who  buys  an 
untried  invention  takes  all  the  risk  of  its  success. 

It  is  Reliable. 

The  long  list  of  purchasers,  extending  over 
thirty  years,  the  continued  and  repeated 
orders  from  those  who  know  it  best,  with  the 
fact  that  it  has  made  its  way  against  all  oppo- 
sition into  extended  use  in  all  parts  of  the  known 
world,  and  into  the  most  exacting  trades, 
demanding  the  establishment  of  manufactories 
in  four  countries,  is  sufficient  proof  on  this  point. 

It  is  Economical. 

The  table  given  of  thirty  tests,  extending  from 
Glasgow  to  San  Francisco,  with  many  kinds  of 
coal,  and  under  many  conditions,  in  which  an 
aggregate  of  over  thirty-ojte  hundred  tons  of 
water  were  evaporated,  with  a  little  over  two 
hundred  and  seventy  tons  of  combustible,  shows 
an  actual  economy  within  about  seven  per  cent, 
of  the  highest  theoretically  practical  under 
similar  conditions.  It  is  quite  safe  to  say  that 
no  other  boiler  can  show  a  better  record  for 
economy. 

It  is  Safe. 

On  this  point  the  record  is  complete.  Boilers 
developing  nearly  two  million  horse- 
power, sold  during  thirty  years  without  loss  of 
life  or  property  by  explosion,  is  a  record  without 
parallel.  Other  so-called  "Safety"  boilers 
have  exploded,  but  the  Babcock  &  Wilcox 
never,  though,  probably,  more  of  them  have 
been  put  into  use  than  of  all  others  combined. 
There  are  boilers  now  offered  in  the  market  as 
' '  Safety  ' '  boilers  which  have  no  other  claim  to 
the  distinction  than  the  deceptive  name. 


^ 


117 


■►-< 


It  is  Durable. 
The  wonderful  record  of  over  one  hundred 
thousand  horse-poiuer  of  these  boilers  in  use 
from  two  to  twenty  years,  many  of  them  driven 
day  and  night,  on  which  the  average  cost  of 
repairs  has  not  exceeded  FIVE  CENTS 
YEARLY  PER  HORSE-POWER  for  the 
boiler  proper  from  all  causes,  speaks  volumes 
on  this  point.  What  does  it  mean  ?  It  means 
that  the  wear  and  tear,  including  accidents,  on 
the  average  is  about  otie-half  of  one  per  cent, 
per  annum  upon  the  cost  (not  including  furnaces 
and  masonry),  while  that  of  a  tubular  boiler  is 
rarely  estimated  at  less  than  ten  per  cent.  As 
to  the  lifetime  of  a  Babcock  &  Wilcox  boiler, 


Side  View  of 
Vertical  Header. 


Front  View  of 
Vertical  Header. 


experience  so  far  fixes  no  data  for  a  limit. 
Thirty  years'  use  has  developed  no  single 
instance  of  a  boiler  being  worn  out  in  legitimate 
service,  and  when  worn  or  damaged  small  repair 
has  apparently  restored  them  to  their  pristine 
youth.     We  see  no  reason  to  suppose  that  at 


the  end  of  fifty  years,  with  the  occasional  re- 
placing of  damaged  parts,  they  may  not  be  "as 
good  as  new." 

For  many  years  we  published  in  this  book  a 
list  of  the  users  of  the  Babcock  &  Wilcox 
boilers  but  the  list  has  become  so  large  that  we 
are  forced  to  omit  it.  To  anyone  desiring 
references  we  shall  be  glad  to  furnish  as  many 
as  desired. 

The  following  summary  will  give  something 
of  an  idea  of  extensive  use  of  Babcock  &  Wilcox 
boilers  in  different  industries  :  — 

Horse-Power. 

Agricultural  Machinery, 8,776 

Bolts,  Screws,  and  Nails, 5,6''9 

Bricks  and  Cement,     . 10,456 

Cable  Railways, 27>io4 

Carpets  and  Oilcloth,        7,258 

Cars,  Wagons,  and  Bicycles, 7,290 

Chemicals,  Glue,  and  Fertilizer, 39,494 

Clothing  and  Furnishing  Goods, 3,794 

Coffee  and  Spices,        2,683 

Confectioners, 3,104 

Copper,  Brass,  Etc., 16,041 

Cotton  and  Linen  Mills, 99,256 

Destructor  Works, 1,891 

Distillers  and  Brewers, 24,016 

Dye  Works  and  Bleacheries, 11,641 

Electric  Railways 200,302 

Electric  Lighting, 233,283 

Electrical  Engineering  and  Supplies, 15,675 

Export  (not  included  under  other  headings),       .     .     .  42,508 

Firearms  and  Ammunition,       4,772 

Flour  Mills  and  Bakeries, 20,697 

Foundries, 6,064 

Gas  Works, 19, 594 

Glass  Works, io,8S6 

Government  Works, 16,407 

Heating  (Central  Stations), 28,240 

Heating  and  Power  for  Buildings, 85,256 

Ice  Making  and  Refrigerating, 11,336 

Iron  and  Steel, 166,496 

Jewelry, 650 

Leather  Works,       4,540 

Locomotives,  Boiler  Makers,  and  Engines,    ....  ,4,087 

Lumber  and  Wood  Working, 14,841 

Machinery,  Tools,  and  Hardware, 35,270 

Mining, 104,237 

Musical  Instruments, 731 

Oils,  Paints,  and  Soap, 33,834 

Packers  and  Canners,       .     .     .' 5,479 

Paper  Mills, 31,069 

Printers  and  Printers'  Supplies, 6,851 

Rope,  Hemp,  Etc., 4,676 

Sewing  Machines, 10,860 

Silk  Mills, " 4,257 

Steam  Roads, 11,652 

Sugar  Refiners, 121,863 

Sugar  Plantations, 70,009 

Tobacco  and  Snuff, 4,141 

Tube  Works, 10,403 

Unclassified 27,238 

Water  Works, 37,151 

Wire  Works,        13, 539 

Woolen  Mills, 22,446 

Total  Horse-Power,      1,709,813 


^ 


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121 


AVERAGE   COST   OF   REPAIRS 

OF  BABCOCK  &  WILCOX  BOILERS  IN  THE  PAST  SEVENTEEN  YEARS. 


The  following  facts  are  gathered  from  a    large    number  of    answers   to    a    circular   of  inquiry    sent   to   all  our  older 

customers.      Sufficient    replies    were    received  to    include    over    lOOfiOO    horse-poiver,  the  repairs  to  the  heating 

surface  of  which,  dice  to  all  causes,  have  averaged    less  than    J  cents  per  horse-power  per  year,  of  ^00 

days  at  12  hours  per  dav  ',  boilers  luliich  have  ricn  night  a7id  day  being  credited  with  the  extra 

running  time.        The  list  would  have   been   more  complete,  and  made   a  still  better 

shozuitig,  but  for  the  fact  that  a  number  of  our  best  customers  declined 

to  give  facts  pertaining  to   their   business  for  J>icblication. 


DeCASTRO    &    DONNER   SUGAR   REFINING     Co. 

2SS0  H.P.  Average  time,  13.6  years,  night 
and  day.     Total  repairs,  6c.  yearly  per  H.P. 

Singer' Manufacturing  Co.  (Case  Factory), 
South  Bend,  Ind.,  900  H.P.  Average  time, 
i2_^  years.    Total  repairs,  j^gC.  yearly  per  H.P. 

"  Verj'  bad  feed- water carry  heavy  fires  and  force 

them  beyond  their  rated  capacity in  one  instance  we  had 

to  replace  two  heads  and  four  tubes  that  were  broken  and 
blistered  by  a  careless  fireman  heating  an  empty  boiler  red 
hot,  ajtd  then  turning  on  the  feed-water  .'.'  Instead  of  a 
disastrous  explosion  that  would  ha^'e  followed  with  other 
boilers,  we  lost  the  above  parts  and  two  days'  time." 

Leighton  Pine,  Manager. 

American  Glucose  Co.,  Buffalo,  N.  Y.  3050 
H.P.  Average  time,  9.8  years.  Total  re- 
pairs, 4c.  yearly  per  H.P. 

New  York  Steam  Co.  13900  H.P.  Average 
time,  3.92  years,  night  and  day.  Total  repairs, 
%c  yearty  per  H.P. 

Rosamond  Woolen  Co.,  Almonte,  Ont.  360 
H.P.  Average  time,  8^  years.  Total  re- 
pairs, ItVc.  yearly  per  H.P. 

Bound  Brook  Woolen  Mills.  600  H.P. 
Average  time,  8.1  years.  Total  repairs,  2c. 
yearly  per  H.P. 

Raritan  Woolen  Mills.  1060  H.P.  Aver- 
age time,  6.7  years.     Total  repairs,  nothing. 

E.  C.  Knight  &  Co.,  Philadelphia.  2000  H.P. 
Average  time,  ^%  years.  Total  repairs,  ic. 
yearly  per  H.P. 

Conglomerate  Mining  Co.  1800  H.P.  Aver- 
age time,  3  3'ears.     Total  repairs,  nothing. 

"  The  boilers  in  every  way  come  up  to  our  highest  ex- 
pectations." Henry  C.  Davis,  Pres't. 

Boston  Sugar  Refining  Co.  1250  H.P. 
Average  time,  ^%  years.  Total  repairs,  4rVc. 
yearly  per  H.P. 


"  Were  put  in  early  in  i? 
night  and  day  ever  since. " 


) ;  have  been  in  constant  use 


C.  Gilbert,  Des  Moines,  Iowa.  488  H.P. 
Average  time,  5  years.  Total  repairs,  2>to^- 
yearly  per  H.P. 

Brooklyn  Sugar   Refining  Co.     3464  H.P. 

Average  time,  7>^  years,  running  night  and 

day.     Total  repairs,  i%c.  yearly  per  H.P. 
John  Crossley  &  Sons,  Limited,  Plantation, 

Louisiana.      1260  H.P.      Average  time,   2>% 

years.     Total  repairs,  nothing. 


Portage  Straw  Board  Co.,  Circleville,  O. 
1472  H.P.  Average  time,  3K  years.  Total 
repairs,  3t'oC.  yearly  per  H.I-. 

"  These  boilers  have  been  worked  hard  a  great  portion  o* 
time  and  have  given  good  satisfaction. " 

Jno.  L.  Taflin,  Manager. 

Bay  State  Sugar  Refining  Co.,  Boston. 
798  H.P.  Average  time,  7.3  years.  Total 
repairs,  jVc  yearly  per  H.P. 

"These  boilers  have  been  constantly  driven  at  their 
highest  capacity  ever  since  their  installation,  until  the  present 
winter,  and  the  cost  of  repairs  to  heating  surfaces  in  that 
time  has  been  $82.53."  J.  F.  Stillman,  Supt. 

Wheeler,  Madden  &  Clemsen  M'f'g  Co., 
Middletown,  N.  Y.  244  H.P.  Average  time, 
5  years.     Total  repairs,  nothing. 

"  We  think  this  a  very  good  record,  and  are  very  much 
pleased  with  the  boilers." 

Joel  H.  Gates,  Burlington,  Vt.  244  H.P. 
Average  time,  5  years.    Total  repairs,  nothing. 

Rumford  Chemical  Works.  279  H.P.  Aver- 
age time,  5  years.     Total  repairs,  nothing. 

"  No  expense  on  account  of  repairs  to  heating  surfaces 
for  either  of  them,  since  they  were  put  in." 

N.  D.  Arnold,  Treas. 

Tytus  Paper  Co.,   Middletown,  O.     650  H.P. 

Average  time,  6  years,  night  and  day.     Total 

repairs,  6>^c.  yearly  per  H.P. 
SoLVAY  Process  Co.,  Syracuse,   N.  Y.      3456 

H.P.,  from  6  to   1)4.   years.      Average  time, 

2.6  years,  night  and  day.     Total  repairs,  i)^c. 

yearly  per  H.P. 

"The  only  repairs  we  have  had  to  make  are  for  new  tubes 
when  they  have  been  burnt  out.  As  you  are  well  aware 
the  water  which  we  use  at  Syracuse  is  very  hard  upon  boiler 
tubes,  and  we  suppose  we  have  burnt  out  more  on  this  ac- 
count than  if  the  water  had  been  good." 

F.  R.  Hazard,  Treas. 
"  I  believe  our  repairs  would  have  been  greater  had  we 
used  the  tubular  type  of  ordinary  design." 

W.  B.  Cogswell,  Manager. 

The  Wardlow  Thomas  Paper  Co.,  Middle- 
town,  O.  600  H.P.  Average  time,  6  years. 
Total  repairs,  nothing. 

"  Easily  managed,  economical  in  coal,  attendance,  and 
repairs ;  and  the  element  of  safety  under  our  hard  firing  is  a 
source  of  much  satisfaction  to  us." 

O.  H.  Wardlow,  Pres't. 

W.  A.  Wood,  M.  &  R.  M.  Co.  360  H.P. 
Average  time,  \-f-^  years.  Total  repairs,  ItqC. 
yearly  per  H.P. 

"  We  consider  them  as  good  as  new  to-day,   and  can 
recommend  them  as  economical  both  in  repairs  and  fuel." 
J.  M.  Rosebrooks,  Sup't. 


^ 


123 


-¥< 


Marcus  Moxham  &  Co.,  bwansea,  v\^ales. 
104  H.P.     Average  time,  3^  years. 

"  It  has  not  cost  us  a  penny  for  repairs." 

Laing,  Wharton  &  Down,  Elcctriciaiis, 
London.     85  H.P.     Average  time,  2.3  years. 

"  As  regards  repairs  they  have  got  to  come,  as  they  have 
not  yet  cost  anything." 

Carnegie  Brothers  &  Co.,  Pittsburgh,  900 
H.P.  Average  time,  5  years.  Total  repairs, 
IjVc.  yearly  per  H.P. 

"The  total  repairs  to  heating  surfaces  in  that  time  have 
been  ^50."  Carnegie  Bros.  &  Co. 

Ransomes,  Sims  &  Jefferies,  L'd,  Ipswich, 
England.  35  H.P.  Average  time,  4>^  years. 
Total  repairs,  nothing. 

"  The  repairs  appear  to  liave  been  about  ;^7  for  brick- 
work." R.\NSOMEs,  Sims  &  Jefferies,  L'd. 

Crocker  Chair  Co.,  Sheboygan,  Wis.  225 
H.P.  Average  time,  7  years.  Total  repairs, 
ic.  yearly  per  H.P. 

"  The  total  cost  of  repairs  to  heating  surfaces  in  that 
time  has  been  not  to  exceed  ^15.  We  do  not  hesitate  to  say 
that  it  is  the  best  boiler  we  have  ever  used." 

Eagle  Paper  Co.,  Franklin,  O.  250  H.P. 
Average  time,  \}i  years.  Total  repairs,  22c. 
yearly  per  H.P. 

"  We  are  well  pleased  with  them." 

D.  B.  Anderson,  Manager. 

FlELDHOUSE  &  DuTCHER  MANUFACTURING  Co., 

Chicago.      75  H.P.     Average  time,  6  years. 
Total  repairs,  iiyVc.  yearly  per  H.P. 

"  Consider  your  boiler  to  be  the  most  economical  and 
best  made." 

Louisiana  Sugar  Refining  Co.  960  H.P. 
Average  time,  5>^  years. 

"  The  cost  of  repairs  is  very  moderate." 

John  S.  Wallis,  Pres't. 

North  Bend  Plantation,  Louisiana.  400 
H.P.  Average  time,  10  j^ears.  Total  repairs, 
ii^c.  yearly  per  H.P. 

Francis  Axe  Co.  136  H.P.  Average  time, 
5to  years.     Total  repairs,  nothing. 

Welham  Estate,  Louisiana.  240  H.P.  Aver- 
age time,  2  years.     Total  repairs,  nothing. 

"  I  have  used  the  boiler  with  perfect  satisfaction.  " 

Wm.  E.  Brickell,  Agent. 

Joseph  Schofield  &  Co.,  Littleboro,  Man- 
chester. 156  H.P.  Average  time,  2^4^  years. 
Total  repairs,  i)4c.  yearly  per  H.P. 

Seth  Thomas  Clock  Col  125  H.P.  Average 
time,  7  years.     Total  repairs,  nothing. 

"  The  only  cost  has  been  the  amount  spent  on  account 
of  burning  up  of  fire-box  furnace  brick." 

Wallace  &  Sons.  400  H.P.  Average  time, 
7  years.     Total  repairs,  j'qC.  yearly  per  H.P. 

"  They  are  apparently  in  perfect  condition  now." 

Foss  &  Barnett.  12,5  H.P.  Average  time, 
7  years.     Total  repairs,  nothiiig. 

"  Have  not  cost  one  dollar  for  repairs — simply  new  grate 
bars.     Think  they  are  good  economical  boilers. 


Cortland  Wagon  Co.  82  H.P.  Average 
time,  6  years.     Total  repairs,  nothing. 

"  No  outlay  for  repairs.  We  consider  this  remarkable 
because  we  have  forced  the  boiler  from  the  beginning. 

Eagle  Square  Manufacturing  Co.,  South 
Shaftsbury,  Vt.  200  H.P.  Average  time, 
^Yz  years.     Total  repairs,  nothhig. 

"  Have  purchased  a  few  fire  brick  to  go  Ijetween 
tubes.     We  have  found  no  other  repairs  necessary." 

F.  L.  Mattison,  Treas. 

Paine  Lumber  Co.,  Oshkosh,  Wis.  416  H.P. 
Average  time,  4  years.   Total  repairs,  nothing. 

"  Have  been  using  the  ordinary  boilers  with  both  large 
and  small  tubes  for  thirty  years  past,  and  regard  your  boilers 
as  more  economical." 

Paine  Lumber  Co. — A.  B.  Ideson. 

P.  P.  Mast  &  Co.,  Springfield,  O.  85  H.P. 
Average  time,  8)^  years,  night  and  day. 
Total  repairs,  3t'oC.  yearly  per  H.P. 

"  We  regard  it  as  the  best  boiler  ever  used  by  our  Com- 
pany, and  think  it  has  no  equal  in  the  market.  After  all  this 
hard  usage,  equal  to  14  years,  we  find  it  still  in  good  con- 
dition." P.  P.  Mast&  Co. 

Edison  Electric  Illuminating  Co.  of  Piqua, 
O.  100  H.P.  Average  time,  5>^  years. 
Total  repairs,  4i-Vc-  yearly  per  H.P. 

Hallet  &  Davis  Co.,  Boston.  104  H.P. 
Average  time,  6  years.  Total  repairs,  5c. 
yearly  per  H.P. 

"  Our  repairs  to  boiler  have  been  for  new  nipples  in  mud- 
drum  in  Aug.,  1887,  which  is  certainly  a  very  creditable 
showing."  Hallet  &  Davis  Co. 

H.  D.  Smith  &Co.,  Plantsville,  Conn.  75  H.P. 
Average  time,  8  years.  Total  repairs, 
nothing. 

"  We  know  of  no  other  boiler  that  would  do  the  work 
that  this  is  doing."  H.  D.  Smith  &  Co. 

F.  A.  PoTH  Brewing  Co.,  Philadelphia.  400 
H.P.  Average  time,  4  years.  Total  repairs, 
iy%c.  yearly  per  H.P. 

J.  L.  Clark,  Oshkosh,  Wis.  107  H.P.  Aver- 
age time,  6Y  years.  Total  repairs,  -^^c.  yearly 
ppr  H.P. 

"  Develop  at  least  one-third  more  work  than  rated.  We 
cannot  speak  too  highly  of  your  boilers.  The)'  are  simply 
perfect."  J.  L.  Clakk. 

Societa  Generale  Italiana  di  Elettricita, 
SiSTEMA  Edison,  Milan,  Italy.  1476  H.P. 
Average  time,  3)^  years. 

"  The  repairs  have  consisted  in  the  changing  of  4  tubes 
and  about  220  rivets  (not  counting  the  last  accident  due  to 
carelessness  of  the  firemen)". 

L'Amministratore  Delegato — J.  Columba. 

Union  Iron  Works,  Johnstone,  Scotland. 
104  H.P.  Average  time,  5  years.  Total  re- 
pairs, 3c.  yearly  per  H.P. 

P.  &  P.  Campbell,  Perth,  Scotland.  146  H.P. 
Average  time,  2  years. 

"  The  boilers  have  cost  nothing  for  repairs  themselves, 
but  the  doors  and  furnace  have  cost  about  £4  los.  per 
annum."  P.  &  P.  Campbell. 


►  "4- 


125 


*■ 


St.  Paul   Building,   New   York.      420  H.P.   Babcock  &  Wilcox   Boilers. 


Cheney  Bros.,  So.  Manchester,  Conn.  350 
H.P.     Average  time,  7  years. 

"  Running  steadily  for  seven  years,  and  during  that  time 
they  have  not  cost  us  anything  for  repairs  to  the  heating 
surfaces."  Cheney  Bros. 

Toledo  &  Ohio  Central  R.  R.  120  H.P. 
Average  time,  7 %  years.  Total  repairs,  lay^gC. 
yearly  per  H.P. 

"The  boilers  have  given  entire  satisfaction  in  every 
respect."  J.  B.  Morgan,  Master  Mechanic. 

McAvov  Brewing  Co.,  Chicago.  832  H.P. 
Average  time,  6  years.  Total  repairs,  loc. 
yearly  per  H.P. 

"  Our  experience  with  them  has  been  to  our  entire  satis- 
faction." Geo.  Dickinson,  Sec'y- 

(Note.  —One-half  of  total  expense  was  due  to  broken 
headers  caused  by  low  water,  because  of  water  combination 
becoming  shut  off. ) 

Cornwall   Bros.,    Louisville,   Ky.     227  H.P. 

Average  time,  8X  years.     Repairs,  nothing. 
Maginnis  Cotton  Mill,  New  Orleans.     624 

H.P.     Average  time,  6  years.     Total  repairs, 

iy%c.  yearly  per  H.P. 

Pioneer  Mills.  150  H.P.  Average  time,  <^]A, 
years.     Total  repairs,  "slight." 

"  Cost  of  repairs  comparatively  nothing.  No  leaking  of 
flues  or  boiler  at  any  time." 

J.  A.  M.  Johnston,  Agent. 

Lawrence  Rope  Works,  Brooklyn.     250  H.P. 

Average  time,    7   years.      Total  repairs,    4c. 

yearly  per  H.P. 
James  Martin  &  Co.,  Philadelphia.      208  H.P. 

Average  time,  7^^  years.     Total  repairs,  i6c. 

yearly  per  H.P. 

"  There  has  been  but  little  cost-  for  repairs  to  them, 
those  we  have  made  being  for  a  few  new  tubes  that  became 
clogged  or  coated  with  scale  on  account  of  the  very  hard 
{well)  water  we  are  using.  We  cannot  speak  too  highly  of 
them."  Jas.   Martin  &  Co. 

Fairmount  Worsted  Mills,  Philadelphia.  400 
H.P.  Average  time,  7.5  years.  Total  re- 
pairs, 6r'oC.  yearly  per  H.P. 

Wm.  Whitaker  &  Sons,  Philadelphia.  480  H. 
P.  Average  time,  7  years.  Total  repairs, 
nothing. 

Vanderbilt  University,  Nashville,  Tenn. 
200  H.P.  Average  time,  6  years.  Total  re- 
pairs, 4c.  yearly  per  H.P. 

"  Cost  of  repairs  to  heating  surface  on  all  the  above 
during  that  time  has  been  $48.25.  The  boilers  during  that 
time  have  given  entire  satisfaction." 

Olin  H.  Landreth,  Dean  of  Engineering  Dept. 

Arlington  Mills  Manufacturing  Co.  500 
H.P.  Average  time,  8  years.  Total  repairs, 
nothing. 

Somerset  Manufacturing  Co.,  Raritan,  N.  J. 
720  H.P.  Average  time,  7.5  years.  Total  re- 
pairs, nothing. 

New  York  &  Brooklyn  Bridge.  600  H.P. 
Average,  2}4,  years.     Total  repairs,  nothing. 

"  The  boilers  have  done  excellent  service  and  have  given 
entire  satisfaction."        C.  C.  Martin,  Ch.  Eng.  &  Supt. 


Church  &  Co.,  Brooklyn,  E.D.  584  H.P. 
Average  time,  4.2  years.    Repairs,  nothing. 

Economist  Plow  Co.,  South  Bend,  Ind.  150 
H.P.  Average  time,  5  years.  Total  repairs, 
nothing. 

"  We  believe  it  to  be  the  most  durable  boiler  made." 
Leighton  Pine,  Pres't. 

Union  Metallic  Cartridge  Co.,  Bridgeport, 
Conn.  276  H.P.  Average  time,  4)^  years. 
Total  repairs,  nothing. 

"The  cost  of  repairs  to  heating  surfaces  of  said  boilers 
in  that  time  has  been  nothing.  We  carry  from  75  to  80  lbs. 
all  the  time."  A.   C.   Hobbs,  Supt. 

Warder,  Bushnell  &  Glessner  Co.  650 
H.P.  Average  time,  3^  years.  Total  re- 
pairs, 4r%c.  yearly  per  H.P. 

"The  boilers  are  giving  us  the  best  satisfaction." 

Chas.  a.  Bauer,  Gen'l  Manager. 

Chicago  City  Railway  Co.  iooo  H.P.  Aver- 
age time,  7  years,  night  and  day.  Total  re- 
pairs, 4xVc.  yearly  per  H.P. 

"  The  boilers  have  worked  well  and  proved  very  satis- 
factory." C.  B.  Holmes,  Sup't. 

Sheboygan  Manufacturing  Co.  333  H.P. 
Average  time,  8  years.  Total  repairs,  4c. 
yearly  per  H.P. 

"  We  have  found  them  economical,  easily  kept  in  run- 
ning order,  and  in  all  ways  entirely  satisfactory,  and  should 
we  need  additional  power  would  use  no  other  boilers." 

G.   L.   Holmes,  Pres't  and  Gen'l  Manager. 

Jackson  &  Sharp  Co.,  Wilmington,  Del.  467 
H.P.  Average  time,  Sj\  years.  Total  re- 
pairs, iiVc.  yearly  per  H.P. 

"  Have  cost  7iothing  for  repairs  to  heating  surfaces, 
except  through  the  carelessness  of  our  fireman,  who,  soon 
after  starting  the  first  boilers,  allowed  the  water  to  get  too 
low  and  burst  three  or  four  headers,  but  doing  no  other 
damage.  We  consider  them  safe  and  economical  steam 
generators." 

The  Jackson  &  Sharp  Co.,  by  Chas.  S.  Robb. 

South  Bend  Toy  Manufacturing  Co.  61  H. 
P.  Average  time,  4  years.  Total  repairs, 
2^c.  yearly  per  H.P. 

"  We  consider  these  boilers  the  safest  and  most  econom- 
ical in  the  market."  F.  H.   Badet,  Sec.  &  Treas. 

Columbus  Buggy  Co.,  Columbus,  O.  800  H. 
P.  Average  time,  7  years.  Total  repairs, 
ij^oC.  yearly  per  H.P. 

"  We  consider  them  the  best  boiler  in  the  market  and 
we  are  now  evaporating  9  lbs.  of  water  to  one  pound  of 
poor  slack  coal."  Fred.  Weadon,  Supt. 

Edison  Electric  Illuminating  Co.  of  N.  Y. 
900  H.P.  Average  time,  7  years.  Total  re- 
pairs, nothing. 

"  They  give  plenty  of  dry  steam  and  have  been  abso- 
lutely tight  at  all  times.  The  boilers  have  shown  unusual 
ability  to  carry  a  constant  pressure  under  the  extreme  and 
sudden  fluctuations,  which  are  unavoidable  in  an  electric 
light  station."  C.   E.  Chinnock,  V.  Pres. 

Kennesaw  Mills  Co.,  Marietta,  Ga.  200  H. 
P.  Average  time,  7  years.  Total  repairs, 
2j%c,  yearly  per  H.P. 

"  You  will  see  that  the  repairs  on  our  boilers  have  not 
cost  very  much  for  the  last  7  years. "       J.  R.   Buchanan. 


►"4- 


127 


Babcock  &  Wilcox  Marine  Water  Tube  Boiler, 


►i^ 


-^ 


E.  Greenfield's  Son  &  Co.,  Brooklyn.  i6o 
H.P.     Average  time,  4  years. 

"  They  show  no  signs  of  wear,  therefore  probably  will 
not  need  repairing  for  some  time  to  come.  We  consider 
them  the  best  boilers  we  have  ever  used." 

Black  &  Germer,  Erie,  Pa.  92  H.P.  Aver- 
age time,  4  years.     Total  repairs,  tiothing. 

"  Is  easily  cared  for  and  economical  in  the  consumption 
of  fuel." 

Planters  Sugar  Refining  Co.,  New  Orleans. 
292  H.P.  Average  time,  6  years.  Total  re- 
pairs, nothing. 

"  The  only  expense  attached  to  them  has  been  new  grate 
bars  and  fire  brick  work."  John  Barkley,  Pres'l. 

S.  S.  Hepworth,  Yonkers,  N.  Y.  104  H.P. 
Average  time,  4yV  years. 

"  During  all  this  time  it  gave  no  trouble  whatever,  and 
did  not  cost  one  penny  for  repairs." 

Wilson  &  McCallay  Tobacco  Co.  300  H. 
P.  Average  time,  5  years.  Total  repairs, 
A^ic.  yearly  per  H.P. 

John  Collins,  Denny,  North  Britain.  425  H. 
P.     Average  time,  Sj^  years. 

"  The  repairs  to  heating  surfaces  have  been  slight,  and 
caused  by  an  unfortunate  admission  of  grease  to  feed  water 
in  the  case  of  my  140  H.P.  boiler.  With  this  exception, 
which  of  course  arose  from  no  fault  of  yours,  the  boilers 
have  done  good  and  heavy  work  and  given  me  satisfaction." 

John  Collins. 

Singer  Manufacturing  Co.,  Kilbowie,  Scot- 
land. 2106  H.P.  Average  time,  4}^  years. 
Total  repairs,  |c.  yearly  per  H.P. 

"  We  have  much  pleasure  in  sending  you  particulars  of 
boilers  as  requested.  .  .  .  Total  repairs,  ;£3.  ig.  3,  which 
■we  consider  highly  satisfactory." 

NovA  Scotia  Sugar  Refinery,  Halifax,  N.  S. 
800  H.P.  Average  time,  7^  years,  night  and 
day.  600  H.P.  since  1880 ;  200  in  1885. 
Total  repairs,  i>^c.  yearly  per  H.P. 

"We  have  pleasure  in  saying  we  consider  them  first- 
class  boilers  in  every  respect."        J.  A.  Turnbull,  Man. 

Kennedy's  Patent  Water  Meter  Co.  L'd., 
Kilmarnock,  Scotland.  51  H.P.  Average 
time,  6  years.     Total  repairs,  nothing. 

"  Repairs  confined  to  re-expanding  one  tube.  The  cost 
■was  trifling. "  Thos.   Kennedy. 

Bent  Colliery  Co.  L'd.  Bothwell,  Scotland. 
480  H.P.     Average  time,  4^-^  years. 

"  The  cost  of  repairs  during  that  time  has  been  trifling. 
I  think  two  short  tubes  were  renewed.  The  boilers  have 
been  constantly  at  work."  J  as.  S.  Dixon. 

Corporation  of  Aberdeen  Gas  Works, 
Scotland.  93  H.P.  Average  time,  3  years, 
night  and  day.     Total  repairs,  nothing. 

"  The  boiler  continues  to  give  great  satisfaction." 

Alex.  Smith. 

The  Square  Works,  Ramsbottom,  England. 
136  H.P.  Average  time,  4  years,  night  and 
day.     Total  repairs,  9tVc.  yearly  per  H.P. 

"Since  Feb.  5th,  1884,  night  and  day  work,  16/6  except 
the  breakdown  through  being  short  of  water,  which  cost 
;£2i.i7.4  to  repair."  Hepburn  &  Co. 


Whitmore  &  Sons,  Edenbridge,  Kent,  Eng» 
land.     100  H.P.     Average  time,  3  years. 

"  Have  not  spent  one  penny  on  the  boiler." 

Miller  &  Co.,  Foundry,  Edinburgh,  Scotland. 
240  H.P.  Average  time,  3  years.  Total  re- 
pairs, nothing. 

"  Only  expense  has  been  some  repairs  to  the  brickwork 
in  connection  with  the  stoker."  Miller  &  Co. 

Carthness  Steam  Saw  Mill,  Wick,  Glasgow. 
146  H.P.  Average  time,  2}i  years.  Total 
repairs,  nothing. 

"  We  are  well  pleased  with  your  boilers,  and  can  with 
confidence  recommend  them  to  any  firm  wishing  to  econo- 
mize their  working  expenses."  Alex.  McEwen. 

Georgie  Mills,  Edinburgh,  Scotland.  146  H. 
P.  Average  time,  3;^  years,  night  and  day. 
Total  repairs,  nothing. 

"  Neither  boiler  has  required  any  repairs  to  heating 
surfaces."  J.  &  G.  Cox. 

J.  &  T.  Boyd,  Iron  Works,  Glasgow.  208  H.P. 
Average  time,  2/^  years. 

"  One  of  these  has  worked  nearly  5  years  and  the  other 
about  half  that  time  without  any  repairs  whatever." 

Dubois  &  Charvet-Colombier,  Armentiferes, 
France.     476  H.P.     Average  time,  3  years. 

"  These  boilers  have  worked  to  our  entire  satisfactiou 
since  2d  November,  1885,  without  as  yet  any  repairs  what- 
ever. " 

Arrol  Brothers,  Bridge  Builders,  Glasgow. 
146  H.P.     Average  time,  5%  years. 

"  Cost  of  repairs  to  heating  surface  is  as  yet  nothing. 
It  gives  us  pleasure  to  hand  you  this  information,  which  is 
entirely  at  your  own  disposal."  Arrol  Bros. 

James  Eadie  &  Sons,  Tube  Works,  Glasgow. 
64  H.P.     Average  time,  5  years. 

"  Repairs  to  heating  surfaces,  none.  " 

Hughes  &  Son.  Meole  Brace,  Shrewsbury, 
England.     61  H.P.     Average  time,  4  years. 

"  Has  up  to  now  cost  us  nothing  whatever  for  repairs. 
We  can  only  repeat  that  we  are  very  much  pleased  in  every 
respect  with  your  boiler." 

Westinghouse  Air  Brake  Co.,  Pittsburgh. 
92  H.P.  Average  time,  4)4  years.  Total  re- 
pairs, 4c.  yearly  per  H.P. 

"  The   repairs   have   been   merely  nominal,   being  con- 
fined to  the  re-expanding  of  a  few  tubes  and  the  replacing 
of  two  or  three  hand  hole  covers,  at  a  total  cost  probably 
not  exceeding  $15.   The  boiler  has  given  entire  satisfaction.  ' 
H.  H.  Westinghouse,  General  Manager. 

Carthage  Water  Works.  122  H.P.  Aver- 
age time,  6)4.  years.     Total  repairs,  nothing. 

"  They  are  practically  as  good  as  when  we  put  them 
in  ;  there  is  not  a   blister  or  scale  on  the  tubes.     The  fire 
has  not  been  out  since  we  first  started  up  in  January,  1882." 
C.  S.   Bartlett,  Manager. 

J.  Pongs,  Jr.,  Newerk,  Germany.  120  H.P. 
Average  time,  3  years. 

"  Has  been  running  3  years  without  needing  any  re- 
pairs up  to  this  time."  J.  Pongs,  Jr. 

CarroN  Co.,  Carron,  Stirlingshire,  N.B.  416 
H.P.  Average  time,  4  years.  Total  repairs, 
nothing. 


129 


-¥4, 


TABLE  OF  CONTENTS. 


I 


Page 

Air,  weight  and  volume  of, 65 

American  coals,  analyses  and  heating  value  of,    ....     52 

Babcock  &  Wilcox  vi^ater-tube  boilers, 39-46 

Advantages, 4^ 

Accessibility  for  cleaning,        46 

Capacity,       45 

Complete  combustion  of  fuel, 41 

Description  of, 39 

Dryness  of  steam, 43 

Durability, 46 

Ease  of  transportation,        46 

Efficient  circulation  of  water, 43 

Freedom  of  expansion,        43 

Joints  removed  from  fire, 41 

Large  draft  area, 41 

Least  loss  of  effect  from  dust, 46 

Practical  experience, 46 

Quick  steaming, 43 

Repairs, 46 

Safety  from  explosion, 43 

Steadiness  of  water  level, 43 

Thin  heating  surface  in  furnace, 41 

Thorough  absorption  of  the  heat, 42 

Unparalleled  record, 117 

Average  cost  of  repairs, 123-129 

Construction,        39 

Erection, 39 

Operation,        41 

Tests  of, i09-:i5,i2i 

Boilers,  care  of, 105 

Efficiency  of, 47 

Importance  of  providing  against  explosion  in,     .     .     .  g 

In  iron  and  steel  works, 63 

Brief  history  of  water-tube  boilers, 27-29 

Burning  green  bagasse,       57 

Calorimeter  trials, 113 

Capacity  of  Babcock  &  Wilcox  boilers, 45 

Care  of  boilers, 105 

Causes  of  explosion, 9 

Caution  necessary  in  the  generation  of  steam,       ....     13 
Chemical  composition  of  several  typical  kinds  of  solid  fuel,     51 

Chimneys, 67 

Size  of,  with  appropriate  horse-powers  of  boilers,  .     .     71 

Circulation  of  water  in  steam  boilers, 19-25,  43 

Coal,  analyses  and  heating  value  of, 52 

Coal,  economy  in  the  use  of, 7 

Combustibles, 51 

Complete  combustion, 41 

Condensers,        55 

Construction  of  Babcock  &  Wilcox  boilers, 39 

Covering  for  boilers,  steam  pipes,  etc., 103 

Description  of  Babcock  &  Wilcox  boilers, 39 

Drying  by  steam, 97 

Dryness  of  steam  in  Babcock  &  Wilcox  boilers,    ....  43 

Durability  of  Babcock  &  Wilcox  boilers, 46 

Dust,  least  loss  of  effect  from, 46 

Ease  of  transportation  of  Babcock  &  Wilcox  boilers,     .     .     46 


Page 
Economy  and  safety  in  steam  generation,    .     .     .     .     .      7-13 

Causes  of  explosion, 9 

Caution  necessary,        13 

How  to  provide  against  explosions, 11 

Importance  of  providing  against  explosion,    ....       9 

Requirements  of  a  perfect  steam  boiler, 7 

Water-tubes  an  element  of  safety, 11 

Economy  in  steam, 47-5° 

Efficiency  of  the  boiler, 47 

Efficiency  of  the  engine,        49 

Efficiency  of  the  furnace, 49 

Efficiency  of  pumping  engines, 50 

Relative    efficiency    of    various    types    of   pumping 

engines, 50 

Economy  of  high  pressure  steam, 83 

Engine  trials, 113 

Equation  of  pipes, 101 

Erection  of  the  Babcock  &  Wilcox  water-tube  boilers,       .     39 
Evolution  of  the  Babcock  &  Wilcox  water-tube  boiler,     31-37 

Factors  of  evaporation,       75 

Feeding  boilers, 83 

Feed  water,  saving  of  fuel  by  heating, 85 

Fire,  temperature  of, 55 

Flow  of  steam  through  a  given  orifice, 99 

Through  pipes, 99 

Fuel, • 50-55 

Proximate  analyses  and  heating  values  of  American 

coals, 52 

Table  of  combustibles, 51 

Table  showing  chemical  combustion  of  several  typical 

kinds  of  solid  fuel, 51 

Geeen  bagasse,  burning  of, 57 

Heating  by  steam, 91 

Heating  liquids  and  boiling  by  steam, 97 

Heating  feed-water, 83 

Heating  from  central  stations, 91 

History  of  water-tube  boilers, 27-29 

Horse-power  of  boilers, ' 6r 

Horse-power  of  different  nations, 61 

How  to  provide  against  explosions, 11 

Importance  of  providing  against  explosion, 9 

Incrustation  and  scale, 89 

Means  of  prevention, 89 

Iron  chimney  stacks, 7^ 

Loss  of  heat  from  steam  pipes, 103 

Large  draft  area  of  Babcock  &  Wilcox  boilers,     ....     41 

Means  of  prevention  of  incrustation  and  scale,     ....     84 
Moisture,  tests  for, 79 

Operation  of  Babcock  &  Wilcox  boilers, 41 

Perfect  steam  boiler,  requirements  of, 7 

Pipes,  equation  of, lo" 

Pipes,  standard  sizes  of  steam  and  gas, loi 

Priming  or  wet  steam, 77 

Properties  of  saturated  steam, 73 

Proximate  analyses  and  heating  values  of  American  coals,  52 


130 


Page 
Quick  steaming, i     .     .     43 

Record  of  Babcock  &  Wilcox  boiler, H7-119 

Relative  efRciency  of  different  types  of  pumping  engines,     50 

Relative  value  of  non-conducting  materials, 103 

Repairs  of  Babcock  &  Wilcox  boilers,     ....    46,123-129 

Requirements  of  a  perfect  steam  boiler, 7 

Riveted  joints, 83 

Rules  and  practical  data, 47 

Saturated  steam. 73 

Saving  of  fuel  by  heating  feed  water, 85 

Scale-making  minerals,  table  of  solubilities  of 75 

Size  of  chimneys  with  appropriate  horse-power  of  boil- 
ers,     . ,    •  71 

Standard  horse-power  for  different  nations 61 

Steadiness  of  water  level, 43 

Steam,  heating  by .  gi 

Heating  liquids  and  boiling  by, 97 


Fage 

Making,  theory  of, 15-19 

Pipes,  loss  of  heat  from, 103 

Superheated, 87,  88 

Temperature  of  fire, , 55 

Testing  steam  boilers,    . 109 

Tests  of  Babcock  &  Wilcox  boilers, 109-115,121 

Calorimeter  trials, 113 

Engine  trials,       113 

Table  of  thirty-two  tests, 121 

Theory  of  steam  making, 15-19 

Water  at  different  temperatures, 75-77 

Water  tubes  an  element  of  safety, 11 

Water-tube  boiler,  brief  history  of  the, 27-29 

Erection  of  the  Babcock  &  Wilcox, 39 

Evolution  of  the  Babcock  &  Wilcox, 31-37 

Weight  and  volume  of  air, 65 

Wet  steam, 77 


LIST  OF  ILLUSTRATIONS. 


Page 

American  Surety  Building, ..••..    66 

Babcock  &  Wilcox  Boiler: — 

Cross  drum  type,  side  view,      .........     30 

"         "         "      front  view .  117 

I        Standard  front, 42 

Side  view  with  superheater, .86 

Front  view  showing  superheater, .87 

Vertical  header,  double  deck, 68 

Vertical  header,  side  view, 40 

Wrought  steel  construction,  side  view, 38 

Babcock  &  Wilcox  Boilers  at — 

Atlas  Cement  Co.'s  works,  Northampton,  Pa.,  ...  70 
Back  Bay  station,  N.   Y.,  N.  H.  &  H.  R.  R.  Co., 

Boston, 10 

Baldwin  Locomotive  works,  Philadelphia,     ....    24 

Bethlehem  Steel  Co.'s  works, 16 

Boott  Cotton  Mills,  Lowell,  Mass 96 

Chavanne,  Brun  et  Cie,  Chamond,  France,   ....     47 
Chelsea  Electricity  Supply  Company's  station,  Chel- 
sea, England 115 

Colorado  Fuel  and  Iron  Company's  works,  Pueblo, 

Colo .63 

Electric     Traction     Company's     Delaware     Avenue 

power  station,  Philadelphia, 90 

Greenfield     &     Company's     confectionery      works, 

Brooklyn,  N.  Y 45 

Harvard  Square  station  of  Boston  Elevated  Railway 

Co.,  Boston,  Mass., 116 

Imperial     Continental     Gas     Association's     works, 

Vienna,    Austria, 124 

Manhattan   Elevated    Railway    Co.'s    station.    New 

York, 108 

Merrimac  Manufacturing  Company's  works,  Lowell, 

Mass., 26 

Metropolitan  Street  Railway  Co.'s  96th    St.  station. 

New  York, 8,  20 

Metropolitan    Street    Railway    Company's    station, 

Kansas  City,  Mo., 114 

Metropolitan    West   Side   Elevated   Railroad   power 

station,  Chicago, 76 

Nikola  Tesla's  laboratory,  New  York  City,  ....  106 
Northwestern   Elevated   R.    R.    Company's   station, 

Chicago, 22 

Pacolet  Mills,  Gainesville,  Ga., 44 

Pittsburgh  Plate  Glass  Co.,  Ford  City,  Pa.,  ....  118 
Ponce  de  Leon  Hotel,  St.  Augustine,  Fla.,  ....  97 
Solvay  Process  Co's  works, 85 


Page 
South  Side  Elevated  R.  R.  Co.'s  station,  Chicago,  .  28 
Spreckels  Beet  Sugar  Factory,  Spreckels,  Calif.,  .  .  78 
U.  S.  Centennial  Exhibition,  Philadelphia,  front  view,     48 

Yngenio  Central  Hormiguero,  Cuba, 56 

Yngenio  Central  Senado,  Cuba,    ........    60 

Babcock  &  Wilcox  Marine  Water  Tube  Boiler 128 

Babcock  &  Wilcox  works, 4 

Bank  of  Commerce   Building  and   New   York   Clearing 

House 104 

Bethlehem  Steel  Company,  works  of, 64 

Boilers,  boiler  house,  and  economizers  for  Seaboard  Oil 

Refinery,  Bayonne,  N.  J., 95 

Chimney  at  Bird  Coleman's  furnace,  Cornwall,  Pa.,  .  .  69 
Colliery  of  the  Lehigh  Valley  Coal  Company,  ....  82 
Colorado  Fuel  and  Iron  Company,  Pueblo,  Colo.,  works 

of, 62 

Cook's  automatic  apparatus  for  burning  green  bagasse  at— 
Yngenio  Central  Hormiguero,  Palmira,  Cuba,  ...     56 

Yngenio  Central  Senado, 60 

Yngenios  Isabel  and  Teresa,  Manzanillo,  Cuba,  plan 

of 58 

Yngenio  Loqueitio,  Cienfuegos,  Cuba,  front  view,     .     59 
Yngenio  Senado,  Nuevitas,  Cuba,  side  view,      ...     57 

Coronado  Beach  Hotel, 12*^ 

Empire  Building,  New  York  City,   .........     74 

Examiner  Building,  San  Francisco, 98 

Exchange  Court  Building,  New  York  City, 100 

Hotel  Ponce  de  Leon,  St.  Augustine,  Fla., 18,  97 

Land  Title  and  Trust  Company  Building,  Philadelphia,     72 

Manhattan  Hotel,  New  York  City, loa 

New  York  and  Brooklyn  Suspension  Bridge, 112 

New  York  City  Hall 84 

New  York  Clearing  House, 104 

Northern  Hospital  for  the  Insane,  Logansport,  Ind.,  .  .  91 
Notre  Dame  Cathedral  and  New  York  Life  Building, 

Montreal,  Canada, no 

Riveting  drum  heads, • 93 

Roman  Catholic  Protectory,  Flatlands,  Pa., 94 

St.  Paul  Building,  New  York  City,     . 126 

Section  Storage, 107 

Spreckels  Sugar  Refinery,  Philadelphia, 12 

Tube  Shed, 105 

United  States  Capitol,  Washington,  D.  C, 120 

Vertical  Headers 119 

Vienna  Opera  House,  Vienna,  Aus., 14 

Waldorf-Astoria  Hotel,  New  York  City, 92 

Washington  Life  Insurance  Building,  New  York  City,     .     80 


131 


■►H 


Date  Due 


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• 

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J 

JUN  ii 

2002 

^ 

Library  Bureau  Cat.  no.  1 137 

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BOSTON  COLLEGE 


3  9031   01460860  8 


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